From b7d72706c3696afafb2519e3ff3715d2bf295606 Mon Sep 17 00:00:00 2001
From: Jirka Borovec <Borda@users.noreply.github.com>
Date: Sat, 8 Aug 2020 00:33:51 +0200
Subject: [PATCH] clean imports (#2867)

* clean imports

* miss
---
 pl_examples/basic_examples/cpu_template.py    |  2 +-
 pl_examples/basic_examples/gpu_template.py    |  2 +-
 .../basic_examples/multi_node_ddp2_demo.py    |  2 +-
 .../computer_vision_fine_tuning.py            |  8 +++----
 pl_examples/domain_templates/imagenet.py      |  2 +-
 .../domain_templates/reinforce_learn_Qnet.py  |  7 +++---
 .../domain_templates/semantic_segmentation.py |  2 +-
 pl_examples/models/lightning_template.py      |  1 -
 pytorch_lightning/accelerators/__init__.py    | 10 ++++-----
 .../accelerators/ddp2_backend.py              |  4 +++-
 pytorch_lightning/accelerators/ddp_backend.py | 12 +++++-----
 .../accelerators/ddp_spawn_backend.py         |  4 ++--
 pytorch_lightning/accelerators/dp_backend.py  |  5 +++--
 pytorch_lightning/accelerators/gpu_backend.py |  1 +
 pytorch_lightning/accelerators/tpu_backend.py |  2 +-
 pytorch_lightning/callbacks/__init__.py       |  2 +-
 pytorch_lightning/callbacks/early_stopping.py |  1 -
 .../gradient_accumulation_scheduler.py        |  1 -
 pytorch_lightning/callbacks/lr_logger.py      |  3 +--
 .../callbacks/model_checkpoint.py             |  4 ++--
 pytorch_lightning/core/hooks.py               |  2 +-
 pytorch_lightning/core/memory.py              |  2 --
 pytorch_lightning/core/saving.py              |  4 ++--
 pytorch_lightning/core/step_result.py         |  8 ++++---
 pytorch_lightning/loggers/__init__.py         |  3 +--
 pytorch_lightning/loggers/csv_logs.py         |  5 +++--
 pytorch_lightning/metrics/__init__.py         | 22 +++++++++----------
 pytorch_lightning/metrics/converters.py       |  3 ++-
 .../metrics/functional/__init__.py            |  2 +-
 .../metrics/functional/classification.py      |  1 -
 pytorch_lightning/metrics/functional/nlp.py   |  2 +-
 pytorch_lightning/overrides/data_parallel.py  |  3 ++-
 .../trainer/auto_mix_precision.py             |  3 +--
 pytorch_lightning/trainer/callback_config.py  |  4 +---
 .../trainer/configuration_validator.py        |  2 +-
 .../trainer/distrib_data_parallel.py          | 18 +++++----------
 pytorch_lightning/trainer/distrib_parts.py    | 18 +++++++--------
 pytorch_lightning/trainer/evaluation_loop.py  |  5 +----
 pytorch_lightning/trainer/logging.py          |  1 -
 pytorch_lightning/trainer/lr_finder.py        |  2 +-
 pytorch_lightning/trainer/trainer.py          |  7 +++---
 pytorch_lightning/trainer/training_io.py      |  3 +--
 pytorch_lightning/trainer/training_loop.py    | 11 +++++-----
 pytorch_lightning/trainer/training_tricks.py  |  7 ++----
 pytorch_lightning/utilities/__init__.py       |  2 +-
 pytorch_lightning/utilities/apply_func.py     |  3 +--
 pytorch_lightning/utilities/cloud_io.py       |  4 ++--
 pytorch_lightning/utilities/distributed.py    |  7 +++---
 pytorch_lightning/utilities/memory.py         |  1 +
 pytorch_lightning/utilities/seed.py           |  4 ++--
 50 files changed, 108 insertions(+), 126 deletions(-)

diff --git a/pl_examples/basic_examples/cpu_template.py b/pl_examples/basic_examples/cpu_template.py
index 613f37105a..9d1fb52495 100644
--- a/pl_examples/basic_examples/cpu_template.py
+++ b/pl_examples/basic_examples/cpu_template.py
@@ -4,8 +4,8 @@ Runs a model on the CPU on a single node.
 import os
 from argparse import ArgumentParser
 
-from pytorch_lightning import Trainer, seed_everything
 from pl_examples.models.lightning_template import LightningTemplateModel
+from pytorch_lightning import Trainer, seed_everything
 
 seed_everything(234)
 
diff --git a/pl_examples/basic_examples/gpu_template.py b/pl_examples/basic_examples/gpu_template.py
index ced4525d4d..64cbabb10b 100644
--- a/pl_examples/basic_examples/gpu_template.py
+++ b/pl_examples/basic_examples/gpu_template.py
@@ -4,8 +4,8 @@ Runs a model on a single node across multiple gpus.
 import os
 from argparse import ArgumentParser
 
-from pytorch_lightning import Trainer, seed_everything
 from pl_examples.models.lightning_template import LightningTemplateModel
+from pytorch_lightning import Trainer, seed_everything
 
 seed_everything(234)
 
diff --git a/pl_examples/basic_examples/multi_node_ddp2_demo.py b/pl_examples/basic_examples/multi_node_ddp2_demo.py
index 1dc73613fb..aead1fba1e 100644
--- a/pl_examples/basic_examples/multi_node_ddp2_demo.py
+++ b/pl_examples/basic_examples/multi_node_ddp2_demo.py
@@ -4,8 +4,8 @@ Multi-node example (GPU)
 import os
 from argparse import ArgumentParser
 
-from pytorch_lightning import Trainer, seed_everything
 from pl_examples.models.lightning_template import LightningTemplateModel
+from pytorch_lightning import Trainer, seed_everything
 
 seed_everything(234)
 
diff --git a/pl_examples/domain_templates/computer_vision_fine_tuning.py b/pl_examples/domain_templates/computer_vision_fine_tuning.py
index 7ebcbf0b7d..21f6644b09 100644
--- a/pl_examples/domain_templates/computer_vision_fine_tuning.py
+++ b/pl_examples/domain_templates/computer_vision_fine_tuning.py
@@ -27,13 +27,10 @@ from pathlib import Path
 from tempfile import TemporaryDirectory
 from typing import Optional, Generator, Union
 
-from torch.nn import Module
-
-import pytorch_lightning as pl
 import torch
 import torch.nn.functional as F
-from pytorch_lightning import _logger as log
 from torch import optim
+from torch.nn import Module
 from torch.optim.lr_scheduler import MultiStepLR
 from torch.optim.optimizer import Optimizer
 from torch.utils.data import DataLoader
@@ -42,6 +39,9 @@ from torchvision import transforms
 from torchvision.datasets import ImageFolder
 from torchvision.datasets.utils import download_and_extract_archive
 
+import pytorch_lightning as pl
+from pytorch_lightning import _logger as log
+
 BN_TYPES = (torch.nn.BatchNorm1d, torch.nn.BatchNorm2d, torch.nn.BatchNorm3d)
 DATA_URL = 'https://storage.googleapis.com/mledu-datasets/cats_and_dogs_filtered.zip'
 
diff --git a/pl_examples/domain_templates/imagenet.py b/pl_examples/domain_templates/imagenet.py
index 20fb1cae24..299c078d17 100644
--- a/pl_examples/domain_templates/imagenet.py
+++ b/pl_examples/domain_templates/imagenet.py
@@ -1,9 +1,9 @@
 """
 This example is largely adapted from https://github.com/pytorch/examples/blob/master/imagenet/main.py
 """
-from argparse import ArgumentParser, Namespace
 import os
 import random
+from argparse import ArgumentParser, Namespace
 from collections import OrderedDict
 
 import torch
diff --git a/pl_examples/domain_templates/reinforce_learn_Qnet.py b/pl_examples/domain_templates/reinforce_learn_Qnet.py
index 026827f70b..cf304f9eb9 100644
--- a/pl_examples/domain_templates/reinforce_learn_Qnet.py
+++ b/pl_examples/domain_templates/reinforce_learn_Qnet.py
@@ -16,12 +16,9 @@ see the metrics:
 tensorboard --logdir default
 """
 
-import pytorch_lightning as pl
-
-from typing import Tuple, List
-
 import argparse
 from collections import OrderedDict, deque, namedtuple
+from typing import Tuple, List
 
 import gym
 import numpy as np
@@ -32,6 +29,8 @@ from torch.optim import Optimizer
 from torch.utils.data import DataLoader
 from torch.utils.data.dataset import IterableDataset
 
+import pytorch_lightning as pl
+
 
 class DQN(nn.Module):
     """
diff --git a/pl_examples/domain_templates/semantic_segmentation.py b/pl_examples/domain_templates/semantic_segmentation.py
index 2f486c5b81..fff3d1cf98 100644
--- a/pl_examples/domain_templates/semantic_segmentation.py
+++ b/pl_examples/domain_templates/semantic_segmentation.py
@@ -1,4 +1,5 @@
 import os
+import random
 from argparse import ArgumentParser, Namespace
 
 import numpy as np
@@ -7,7 +8,6 @@ import torch.nn.functional as F
 import torchvision.transforms as transforms
 from PIL import Image
 from torch.utils.data import DataLoader, Dataset
-import random
 
 import pytorch_lightning as pl
 from pl_examples.models.unet import UNet
diff --git a/pl_examples/models/lightning_template.py b/pl_examples/models/lightning_template.py
index 2b4b201cdd..099d6b5a65 100644
--- a/pl_examples/models/lightning_template.py
+++ b/pl_examples/models/lightning_template.py
@@ -12,7 +12,6 @@ from torch import optim
 from torch.utils.data import DataLoader
 from torchvision.datasets import MNIST
 
-from pytorch_lightning import _logger as log
 from pytorch_lightning.core import LightningModule
 
 
diff --git a/pytorch_lightning/accelerators/__init__.py b/pytorch_lightning/accelerators/__init__.py
index 8230dc4f12..a8f4c14649 100644
--- a/pytorch_lightning/accelerators/__init__.py
+++ b/pytorch_lightning/accelerators/__init__.py
@@ -1,7 +1,7 @@
+from pytorch_lightning.accelerators.cpu_backend import CPUBackend
+from pytorch_lightning.accelerators.ddp2_backend import DDP2Backend
+from pytorch_lightning.accelerators.ddp_backend import DDPBackend
+from pytorch_lightning.accelerators.ddp_spawn_backend import DDPSpawnBackend
+from pytorch_lightning.accelerators.dp_backend import DataParallelBackend
 from pytorch_lightning.accelerators.gpu_backend import GPUBackend
 from pytorch_lightning.accelerators.tpu_backend import TPUBackend
-from pytorch_lightning.accelerators.dp_backend import DataParallelBackend
-from pytorch_lightning.accelerators.ddp_spawn_backend import DDPSpawnBackend
-from pytorch_lightning.accelerators.cpu_backend import CPUBackend
-from pytorch_lightning.accelerators.ddp_backend import DDPBackend
-from pytorch_lightning.accelerators.ddp2_backend import DDP2Backend
diff --git a/pytorch_lightning/accelerators/ddp2_backend.py b/pytorch_lightning/accelerators/ddp2_backend.py
index cc14c44ebe..8a4b0f6584 100644
--- a/pytorch_lightning/accelerators/ddp2_backend.py
+++ b/pytorch_lightning/accelerators/ddp2_backend.py
@@ -13,10 +13,12 @@
 # limitations under the License
 
 import os
+
 import torch
+
+from pytorch_lightning import _logger as log
 from pytorch_lightning.utilities import NATIVE_AMP_AVALAIBLE
 from pytorch_lightning.utilities.distributed import rank_zero_only
-from pytorch_lightning import _logger as log
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
 
 try:
diff --git a/pytorch_lightning/accelerators/ddp_backend.py b/pytorch_lightning/accelerators/ddp_backend.py
index 44ad52d34b..163e3faec8 100644
--- a/pytorch_lightning/accelerators/ddp_backend.py
+++ b/pytorch_lightning/accelerators/ddp_backend.py
@@ -13,16 +13,18 @@
 # limitations under the License
 
 import os
-import torch
 import subprocess
 import sys
-from time import sleep
-import numpy as np
 from os.path import abspath
+from time import sleep
+from typing import Optional
+
+import numpy as np
+import torch
+
+from pytorch_lightning import _logger as log
 from pytorch_lightning.utilities import NATIVE_AMP_AVALAIBLE
 from pytorch_lightning.utilities.distributed import rank_zero_only
-from pytorch_lightning import _logger as log
-from typing import Optional
 
 try:
     from hydra.utils import to_absolute_path, get_original_cwd
diff --git a/pytorch_lightning/accelerators/ddp_spawn_backend.py b/pytorch_lightning/accelerators/ddp_spawn_backend.py
index 704fc55585..fe5b33af47 100644
--- a/pytorch_lightning/accelerators/ddp_spawn_backend.py
+++ b/pytorch_lightning/accelerators/ddp_spawn_backend.py
@@ -12,11 +12,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License
 
-import os
 import torch
 import torch.multiprocessing as mp
-from pytorch_lightning.utilities.distributed import rank_zero_only
+
 from pytorch_lightning import _logger as log
+from pytorch_lightning.utilities.distributed import rank_zero_only
 
 try:
     from apex import amp
diff --git a/pytorch_lightning/accelerators/dp_backend.py b/pytorch_lightning/accelerators/dp_backend.py
index efb683ff4e..a6fb4ca3e3 100644
--- a/pytorch_lightning/accelerators/dp_backend.py
+++ b/pytorch_lightning/accelerators/dp_backend.py
@@ -13,10 +13,11 @@
 # limitations under the License.
 
 import torch
-from pytorch_lightning.utilities.exceptions import MisconfigurationException
-from pytorch_lightning.overrides.data_parallel import LightningDataParallel
 from torch import optim
 
+from pytorch_lightning.overrides.data_parallel import LightningDataParallel
+from pytorch_lightning.utilities.exceptions import MisconfigurationException
+
 try:
     from apex import amp
 except ImportError:
diff --git a/pytorch_lightning/accelerators/gpu_backend.py b/pytorch_lightning/accelerators/gpu_backend.py
index 7f15d3c25f..846457f126 100644
--- a/pytorch_lightning/accelerators/gpu_backend.py
+++ b/pytorch_lightning/accelerators/gpu_backend.py
@@ -15,6 +15,7 @@
 import torch
 
 from pytorch_lightning.core import LightningModule
+
 try:
     from apex import amp
 except ImportError:
diff --git a/pytorch_lightning/accelerators/tpu_backend.py b/pytorch_lightning/accelerators/tpu_backend.py
index 2c0b172b9e..e879af3f5c 100644
--- a/pytorch_lightning/accelerators/tpu_backend.py
+++ b/pytorch_lightning/accelerators/tpu_backend.py
@@ -17,10 +17,10 @@ import os
 import torch
 import torch.multiprocessing as mp
 
+from pytorch_lightning import _logger as log
 from pytorch_lightning.core import LightningModule
 from pytorch_lightning.utilities import rank_zero_info, rank_zero_only, rank_zero_warn
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
-from pytorch_lightning import _logger as log
 
 try:
     import torch_xla
diff --git a/pytorch_lightning/callbacks/__init__.py b/pytorch_lightning/callbacks/__init__.py
index 7e8e0ce5bc..92920ee9b7 100644
--- a/pytorch_lightning/callbacks/__init__.py
+++ b/pytorch_lightning/callbacks/__init__.py
@@ -1,8 +1,8 @@
 from pytorch_lightning.callbacks.base import Callback
 from pytorch_lightning.callbacks.early_stopping import EarlyStopping
 from pytorch_lightning.callbacks.gradient_accumulation_scheduler import GradientAccumulationScheduler
-from pytorch_lightning.callbacks.model_checkpoint import ModelCheckpoint
 from pytorch_lightning.callbacks.lr_logger import LearningRateLogger
+from pytorch_lightning.callbacks.model_checkpoint import ModelCheckpoint
 from pytorch_lightning.callbacks.progress import ProgressBarBase, ProgressBar
 
 __all__ = [
diff --git a/pytorch_lightning/callbacks/early_stopping.py b/pytorch_lightning/callbacks/early_stopping.py
index d60e3d8158..3b4aed8566 100644
--- a/pytorch_lightning/callbacks/early_stopping.py
+++ b/pytorch_lightning/callbacks/early_stopping.py
@@ -7,7 +7,6 @@ Monitor a validation metric and stop training when it stops improving.
 """
 from copy import deepcopy
 
-import os
 import numpy as np
 import torch
 import torch.distributed as dist
diff --git a/pytorch_lightning/callbacks/gradient_accumulation_scheduler.py b/pytorch_lightning/callbacks/gradient_accumulation_scheduler.py
index 9975746440..8d61d29856 100644
--- a/pytorch_lightning/callbacks/gradient_accumulation_scheduler.py
+++ b/pytorch_lightning/callbacks/gradient_accumulation_scheduler.py
@@ -7,7 +7,6 @@ Change gradient accumulation factor according to scheduling.
 """
 
 from pytorch_lightning.callbacks.base import Callback
-from pytorch_lightning.utilities import rank_zero_warn
 
 
 class GradientAccumulationScheduler(Callback):
diff --git a/pytorch_lightning/callbacks/lr_logger.py b/pytorch_lightning/callbacks/lr_logger.py
index 27fbb81800..a401cc8451 100755
--- a/pytorch_lightning/callbacks/lr_logger.py
+++ b/pytorch_lightning/callbacks/lr_logger.py
@@ -8,9 +8,8 @@ Log learning rate for lr schedulers during training
 """
 
 from pytorch_lightning.callbacks.base import Callback
-from pytorch_lightning.utilities.exceptions import MisconfigurationException
-
 from pytorch_lightning.utilities import rank_zero_warn
+from pytorch_lightning.utilities.exceptions import MisconfigurationException
 
 
 class LearningRateLogger(Callback):
diff --git a/pytorch_lightning/callbacks/model_checkpoint.py b/pytorch_lightning/callbacks/model_checkpoint.py
index c0a80d55f3..fc56f5e95c 100644
--- a/pytorch_lightning/callbacks/model_checkpoint.py
+++ b/pytorch_lightning/callbacks/model_checkpoint.py
@@ -8,11 +8,11 @@ Automatically save model checkpoints during training.
 
 import os
 import re
-
-import numpy as np
 from typing import Optional
 
+import numpy as np
 import torch
+
 from pytorch_lightning import _logger as log
 from pytorch_lightning.callbacks.base import Callback
 from pytorch_lightning.utilities import rank_zero_warn, rank_zero_only
diff --git a/pytorch_lightning/core/hooks.py b/pytorch_lightning/core/hooks.py
index 922f500ce8..4b0f9bdd02 100644
--- a/pytorch_lightning/core/hooks.py
+++ b/pytorch_lightning/core/hooks.py
@@ -4,8 +4,8 @@ import torch
 from torch import Tensor
 from torch.nn import Module
 from torch.optim.optimizer import Optimizer
-from pytorch_lightning.utilities import move_data_to_device, NATIVE_AMP_AVALAIBLE
 
+from pytorch_lightning.utilities import move_data_to_device, NATIVE_AMP_AVALAIBLE
 
 try:
     from apex import amp
diff --git a/pytorch_lightning/core/memory.py b/pytorch_lightning/core/memory.py
index 391192615f..b894983a8f 100644
--- a/pytorch_lightning/core/memory.py
+++ b/pytorch_lightning/core/memory.py
@@ -9,9 +9,7 @@ import torch
 import torch.nn as nn
 from torch.utils.hooks import RemovableHandle
 
-
 from pytorch_lightning.utilities import NATIVE_AMP_AVALAIBLE
-from pytorch_lightning.utilities.apply_func import apply_to_collection
 
 PARAMETER_NUM_UNITS = [" ", "K", "M", "B", "T"]
 UNKNOWN_SIZE = "?"
diff --git a/pytorch_lightning/core/saving.py b/pytorch_lightning/core/saving.py
index 20fa8a8840..68749f3f6c 100644
--- a/pytorch_lightning/core/saving.py
+++ b/pytorch_lightning/core/saving.py
@@ -2,11 +2,11 @@ import ast
 import csv
 import inspect
 import os
+from argparse import Namespace
+from typing import Union, Dict, Any, Optional, Callable, MutableMapping
 
 import torch
 import yaml
-from argparse import Namespace
-from typing import Union, Dict, Any, Optional, Callable, MutableMapping
 
 from pytorch_lightning import _logger as log
 from pytorch_lightning.utilities import rank_zero_warn, AttributeDict
diff --git a/pytorch_lightning/core/step_result.py b/pytorch_lightning/core/step_result.py
index 172930fd4a..84f9669cf4 100644
--- a/pytorch_lightning/core/step_result.py
+++ b/pytorch_lightning/core/step_result.py
@@ -1,8 +1,10 @@
 import numbers
-from typing import Optional, Dict, Union, Sequence, Callable, MutableMapping, Any
-from torch import Tensor
-import torch
 from copy import copy
+from typing import Optional, Dict, Union, Sequence, Callable, MutableMapping, Any
+
+import torch
+from torch import Tensor
+
 from pytorch_lightning.metrics.converters import _sync_ddp_if_available
 
 
diff --git a/pytorch_lightning/loggers/__init__.py b/pytorch_lightning/loggers/__init__.py
index 5f2f3044d0..e448060335 100644
--- a/pytorch_lightning/loggers/__init__.py
+++ b/pytorch_lightning/loggers/__init__.py
@@ -1,9 +1,8 @@
 from os import environ
 
 from pytorch_lightning.loggers.base import LightningLoggerBase, LoggerCollection
-from pytorch_lightning.loggers.tensorboard import TensorBoardLogger
 from pytorch_lightning.loggers.csv_logs import CSVLogger
-
+from pytorch_lightning.loggers.tensorboard import TensorBoardLogger
 
 __all__ = [
     'LightningLoggerBase',
diff --git a/pytorch_lightning/loggers/csv_logs.py b/pytorch_lightning/loggers/csv_logs.py
index 1e395abadb..8d3c69dbf3 100644
--- a/pytorch_lightning/loggers/csv_logs.py
+++ b/pytorch_lightning/loggers/csv_logs.py
@@ -5,13 +5,14 @@ CSV logger
 CSV logger for basic experiment logging that does not require opening ports
 
 """
+import csv
 import io
 import os
-import csv
-import torch
 from argparse import Namespace
 from typing import Optional, Dict, Any, Union
 
+import torch
+
 from pytorch_lightning import _logger as log
 from pytorch_lightning.core.saving import save_hparams_to_yaml
 from pytorch_lightning.loggers.base import LightningLoggerBase
diff --git a/pytorch_lightning/metrics/__init__.py b/pytorch_lightning/metrics/__init__.py
index 2a107c639b..65898a5fed 100644
--- a/pytorch_lightning/metrics/__init__.py
+++ b/pytorch_lightning/metrics/__init__.py
@@ -1,13 +1,3 @@
-from pytorch_lightning.metrics.converters import numpy_metric, tensor_metric
-from pytorch_lightning.metrics.metric import Metric, TensorMetric, NumpyMetric
-from pytorch_lightning.metrics.regression import (
-    MAE,
-    MSE,
-    PSNR,
-    RMSE,
-    RMSLE,
-    SSIM
-)
 from pytorch_lightning.metrics.classification import (
     Accuracy,
     AveragePrecision,
@@ -24,12 +14,22 @@ from pytorch_lightning.metrics.classification import (
     PrecisionRecall,
     IoU,
 )
+from pytorch_lightning.metrics.converters import numpy_metric, tensor_metric
+from pytorch_lightning.metrics.metric import Metric, TensorMetric, NumpyMetric
+from pytorch_lightning.metrics.nlp import BLEUScore
+from pytorch_lightning.metrics.regression import (
+    MAE,
+    MSE,
+    PSNR,
+    RMSE,
+    RMSLE,
+    SSIM
+)
 from pytorch_lightning.metrics.sklearns import (
     AUC,
     PrecisionRecallCurve,
     SklearnMetric,
 )
-from pytorch_lightning.metrics.nlp import BLEUScore
 
 __classification_metrics = [
     "AUC",
diff --git a/pytorch_lightning/metrics/converters.py b/pytorch_lightning/metrics/converters.py
index d01ee4e6db..c58a3f55f0 100644
--- a/pytorch_lightning/metrics/converters.py
+++ b/pytorch_lightning/metrics/converters.py
@@ -10,8 +10,9 @@ from typing import Union, Any, Callable, Optional
 import numpy as np
 import torch
 from torch.utils.data._utils.collate import np_str_obj_array_pattern
-from pytorch_lightning.utilities.apply_func import apply_to_collection
+
 from pytorch_lightning.utilities import rank_zero_warn
+from pytorch_lightning.utilities.apply_func import apply_to_collection
 
 try:
     from torch.distributed import ReduceOp
diff --git a/pytorch_lightning/metrics/functional/__init__.py b/pytorch_lightning/metrics/functional/__init__.py
index 4d940ad18b..926803b504 100644
--- a/pytorch_lightning/metrics/functional/__init__.py
+++ b/pytorch_lightning/metrics/functional/__init__.py
@@ -20,6 +20,7 @@ from pytorch_lightning.metrics.functional.classification import (
     to_onehot,
     iou,
 )
+from pytorch_lightning.metrics.functional.nlp import bleu_score
 from pytorch_lightning.metrics.functional.regression import (
     mae,
     mse,
@@ -28,4 +29,3 @@ from pytorch_lightning.metrics.functional.regression import (
     rmsle,
     ssim
 )
-from pytorch_lightning.metrics.functional.nlp import bleu_score
diff --git a/pytorch_lightning/metrics/functional/classification.py b/pytorch_lightning/metrics/functional/classification.py
index d12509d588..83b27a7ab2 100644
--- a/pytorch_lightning/metrics/functional/classification.py
+++ b/pytorch_lightning/metrics/functional/classification.py
@@ -1,4 +1,3 @@
-import sys
 from functools import wraps
 from typing import Callable, Optional, Sequence, Tuple
 
diff --git a/pytorch_lightning/metrics/functional/nlp.py b/pytorch_lightning/metrics/functional/nlp.py
index e1bb86ab19..22645bb549 100644
--- a/pytorch_lightning/metrics/functional/nlp.py
+++ b/pytorch_lightning/metrics/functional/nlp.py
@@ -3,8 +3,8 @@
 # Authors: torchtext authors and @sluks
 # Date: 2020-07-18
 # Link: https://pytorch.org/text/_modules/torchtext/data/metrics.html#bleu_score
-from typing import Sequence, List
 from collections import Counter
+from typing import Sequence, List
 
 import torch
 
diff --git a/pytorch_lightning/overrides/data_parallel.py b/pytorch_lightning/overrides/data_parallel.py
index 3945d770fe..c6e8cd8fa6 100644
--- a/pytorch_lightning/overrides/data_parallel.py
+++ b/pytorch_lightning/overrides/data_parallel.py
@@ -1,13 +1,14 @@
 import itertools
 import threading
-from itertools import chain
 from collections import Mapping, Iterable
+from itertools import chain
 
 import torch
 from torch.cuda._utils import _get_device_index
 from torch.nn import DataParallel
 from torch.nn.parallel import DistributedDataParallel
 from torch.nn.parallel._functions import Gather
+
 from pytorch_lightning.core.step_result import Result
 
 
diff --git a/pytorch_lightning/trainer/auto_mix_precision.py b/pytorch_lightning/trainer/auto_mix_precision.py
index 570bcc3aaf..71ff71d0ec 100644
--- a/pytorch_lightning/trainer/auto_mix_precision.py
+++ b/pytorch_lightning/trainer/auto_mix_precision.py
@@ -1,8 +1,7 @@
 from abc import ABC
 
 from pytorch_lightning import _logger as log
-from pytorch_lightning.utilities import rank_zero_warn, APEX_AVAILABLE, NATIVE_AMP_AVALAIBLE
-from pytorch_lightning.utilities.distributed import rank_zero_debug
+from pytorch_lightning.utilities import APEX_AVAILABLE, NATIVE_AMP_AVALAIBLE
 
 
 class TrainerAMPMixin(ABC):
diff --git a/pytorch_lightning/trainer/callback_config.py b/pytorch_lightning/trainer/callback_config.py
index 8600449d86..6547e7348a 100644
--- a/pytorch_lightning/trainer/callback_config.py
+++ b/pytorch_lightning/trainer/callback_config.py
@@ -1,7 +1,5 @@
-import os
 from abc import ABC, abstractmethod
-from typing import List, Callable, Optional
-
+from typing import List, Optional
 
 from pytorch_lightning.callbacks import Callback, ModelCheckpoint, EarlyStopping, ProgressBarBase, ProgressBar
 from pytorch_lightning.loggers import LightningLoggerBase
diff --git a/pytorch_lightning/trainer/configuration_validator.py b/pytorch_lightning/trainer/configuration_validator.py
index 3c33f33fe5..f4144563a7 100644
--- a/pytorch_lightning/trainer/configuration_validator.py
+++ b/pytorch_lightning/trainer/configuration_validator.py
@@ -1,6 +1,6 @@
 from pytorch_lightning.core.lightning import LightningModule
-from pytorch_lightning.utilities.exceptions import MisconfigurationException
 from pytorch_lightning.utilities import rank_zero_warn
+from pytorch_lightning.utilities.exceptions import MisconfigurationException
 
 
 class ConfigValidator(object):
diff --git a/pytorch_lightning/trainer/distrib_data_parallel.py b/pytorch_lightning/trainer/distrib_data_parallel.py
index 1f92e61e94..f956f63307 100644
--- a/pytorch_lightning/trainer/distrib_data_parallel.py
+++ b/pytorch_lightning/trainer/distrib_data_parallel.py
@@ -131,23 +131,17 @@ import os
 import re
 from abc import ABC, abstractmethod
 from distutils.version import LooseVersion
-from typing import Union, List, Optional, Callable, Tuple
-import subprocess
-import sys
-from time import sleep
-import numpy as np
-from os.path import abspath
-from pkg_resources import parse_version
+from typing import Union, List, Optional, Tuple
 
+import numpy as np
 import torch
+
 from pytorch_lightning import _logger as log
-from pytorch_lightning.loggers import LightningLoggerBase
-from pytorch_lightning.utilities import NATIVE_AMP_AVALAIBLE
-from pytorch_lightning.utilities.exceptions import MisconfigurationException
-from pytorch_lightning.utilities.distributed import rank_zero_only, rank_zero_warn, rank_zero_info
 from pytorch_lightning.core.datamodule import LightningDataModule
 from pytorch_lightning.core.lightning import LightningModule
-
+from pytorch_lightning.loggers import LightningLoggerBase
+from pytorch_lightning.utilities.distributed import rank_zero_warn, rank_zero_info
+from pytorch_lightning.utilities.exceptions import MisconfigurationException
 
 try:
     from apex import amp
diff --git a/pytorch_lightning/trainer/distrib_parts.py b/pytorch_lightning/trainer/distrib_parts.py
index 7d5a00523e..f647f9ca3f 100644
--- a/pytorch_lightning/trainer/distrib_parts.py
+++ b/pytorch_lightning/trainer/distrib_parts.py
@@ -18,25 +18,23 @@ Currently supports training on CPU, GPU (dp, ddp, ddp2, horovod) and TPU.
 
 """
 
-from contextlib import ExitStack
-import os
-from abc import ABC, abstractmethod
-import time
 import random
-import torch
-from torch.optim.lr_scheduler import _LRScheduler
+import time
+from abc import ABC, abstractmethod
+from contextlib import ExitStack
 from typing import Union, Callable, Any, List, Optional, Tuple, MutableSequence
 
+import torch
+from torch.optim.lr_scheduler import _LRScheduler
+
 from pytorch_lightning.core.lightning import LightningModule
-from pytorch_lightning import _logger as log
 from pytorch_lightning.overrides.data_parallel import (
     LightningDistributedDataParallel,
     LightningDataParallel,
 )
-from pytorch_lightning.utilities import move_data_to_device, NATIVE_AMP_AVALAIBLE
-from pytorch_lightning.utilities.exceptions import MisconfigurationException
+from pytorch_lightning.utilities import move_data_to_device
 from pytorch_lightning.utilities.distributed import rank_zero_only
-from pytorch_lightning.utilities import rank_zero_warn
+from pytorch_lightning.utilities.exceptions import MisconfigurationException
 
 try:
     from apex import amp
diff --git a/pytorch_lightning/trainer/evaluation_loop.py b/pytorch_lightning/trainer/evaluation_loop.py
index 75d09db2ce..f2ad3cb4ef 100644
--- a/pytorch_lightning/trainer/evaluation_loop.py
+++ b/pytorch_lightning/trainer/evaluation_loop.py
@@ -131,13 +131,10 @@ import torch
 from torch.utils.data import DataLoader
 
 from pytorch_lightning.core.lightning import LightningModule
-from pytorch_lightning.overrides.data_parallel import LightningDistributedDataParallel, LightningDataParallel
-from pytorch_lightning.utilities import rank_zero_warn, NATIVE_AMP_AVALAIBLE, flatten_dict
-from torch import distributed as dist
 from pytorch_lightning.core.step_result import Result, EvalResult
+from pytorch_lightning.utilities import rank_zero_warn, NATIVE_AMP_AVALAIBLE, flatten_dict
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
 
-
 try:
     import torch_xla.distributed.parallel_loader as xla_pl
     import torch_xla.core.xla_model as xm
diff --git a/pytorch_lightning/trainer/logging.py b/pytorch_lightning/trainer/logging.py
index aced8b64a4..c90ba59abf 100644
--- a/pytorch_lightning/trainer/logging.py
+++ b/pytorch_lightning/trainer/logging.py
@@ -1,4 +1,3 @@
-import os
 from abc import ABC
 from typing import Union, Iterable
 
diff --git a/pytorch_lightning/trainer/lr_finder.py b/pytorch_lightning/trainer/lr_finder.py
index 3b3e992e0e..0c3a9047d9 100755
--- a/pytorch_lightning/trainer/lr_finder.py
+++ b/pytorch_lightning/trainer/lr_finder.py
@@ -1,8 +1,8 @@
 """
 Trainer Learning Rate Finder
 """
-import os
 import importlib
+import os
 from abc import ABC, abstractmethod
 from typing import Optional, Sequence, Tuple, List, Union
 
diff --git a/pytorch_lightning/trainer/trainer.py b/pytorch_lightning/trainer/trainer.py
index 02adf6eb67..9577d3e2a3 100644
--- a/pytorch_lightning/trainer/trainer.py
+++ b/pytorch_lightning/trainer/trainer.py
@@ -20,9 +20,10 @@ from typing import Any, Dict, Iterable, List, Optional, Tuple, Union
 
 import torch
 import torch.distributed as torch_distrib
-import torch.multiprocessing as mp
 from torch.utils.data import DataLoader
 
+from pytorch_lightning.accelerators import (
+    GPUBackend, TPUBackend, CPUBackend, DDPSpawnBackend, DataParallelBackend, DDPBackend, DDP2Backend)
 from pytorch_lightning.callbacks import Callback, EarlyStopping, ModelCheckpoint
 from pytorch_lightning.core.datamodule import LightningDataModule
 from pytorch_lightning.core.lightning import LightningModule
@@ -33,6 +34,7 @@ from pytorch_lightning.profiler import BaseProfiler, PassThroughProfiler, Simple
 from pytorch_lightning.trainer.auto_mix_precision import NATIVE_AMP_AVALAIBLE, TrainerAMPMixin
 from pytorch_lightning.trainer.callback_config import TrainerCallbackConfigMixin
 from pytorch_lightning.trainer.callback_hook import TrainerCallbackHookMixin
+from pytorch_lightning.trainer.configuration_validator import ConfigValidator
 from pytorch_lightning.trainer.data_loading import TrainerDataLoadingMixin
 from pytorch_lightning.trainer.deprecated_api import TrainerDeprecatedAPITillVer0_10
 from pytorch_lightning.trainer.distrib_data_parallel import TrainerDDPMixin
@@ -50,9 +52,6 @@ from pytorch_lightning.trainer.training_tricks import TrainerTrainingTricksMixin
 from pytorch_lightning.utilities import parsing, rank_zero_info, rank_zero_only, rank_zero_warn
 from pytorch_lightning.utilities.debugging import InternalDebugger
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
-from pytorch_lightning.trainer.configuration_validator import ConfigValidator
-from pytorch_lightning.accelerators import (
-    GPUBackend, TPUBackend, CPUBackend, DDPSpawnBackend, DataParallelBackend, DDPBackend, DDP2Backend)
 
 # warnings to ignore in trainer
 warnings.filterwarnings(
diff --git a/pytorch_lightning/trainer/training_io.py b/pytorch_lightning/trainer/training_io.py
index 1c22390355..30e3d7c0e3 100644
--- a/pytorch_lightning/trainer/training_io.py
+++ b/pytorch_lightning/trainer/training_io.py
@@ -89,15 +89,14 @@ import signal
 from abc import ABC
 from distutils.version import LooseVersion
 from subprocess import call
-from pkg_resources import parse_version
 
 import torch
 import torch.distributed as torch_distrib
 
 import pytorch_lightning
 from pytorch_lightning import _logger as log
-from pytorch_lightning.core.lightning import LightningModule
 from pytorch_lightning.callbacks import ModelCheckpoint, EarlyStopping
+from pytorch_lightning.core.lightning import LightningModule
 from pytorch_lightning.loggers import LightningLoggerBase
 from pytorch_lightning.overrides.data_parallel import (
     LightningDistributedDataParallel,
diff --git a/pytorch_lightning/trainer/training_loop.py b/pytorch_lightning/trainer/training_loop.py
index 5df7437348..757826393f 100644
--- a/pytorch_lightning/trainer/training_loop.py
+++ b/pytorch_lightning/trainer/training_loop.py
@@ -157,29 +157,28 @@ in your model.
     trainer = Trainer(terminate_on_nan=True)
 
 """
-import os
 import subprocess
 from abc import ABC, abstractmethod
+from copy import copy
 from typing import Callable
 from typing import Union, List
 
 import numpy as np
 import torch
-from torch.utils.data import DataLoader
 import torch.distributed as torch_distrib
-from copy import copy
+from torch.utils.data import DataLoader
 
 from pytorch_lightning import _logger as log
-from pytorch_lightning.callbacks.base import Callback
 from pytorch_lightning.callbacks import ModelCheckpoint
+from pytorch_lightning.callbacks.base import Callback
 from pytorch_lightning.core.lightning import LightningModule
+from pytorch_lightning.core.step_result import EvalResult, Result
 from pytorch_lightning.loggers import LightningLoggerBase
 from pytorch_lightning.trainer.supporters import TensorRunningAccum, Accumulator
 from pytorch_lightning.utilities import rank_zero_warn, NATIVE_AMP_AVALAIBLE
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
-from pytorch_lightning.utilities.parsing import AttributeDict
 from pytorch_lightning.utilities.memory import recursive_detach
-from pytorch_lightning.core.step_result import EvalResult, TrainResult, Result
+from pytorch_lightning.utilities.parsing import AttributeDict
 
 try:
     from apex import amp
diff --git a/pytorch_lightning/trainer/training_tricks.py b/pytorch_lightning/trainer/training_tricks.py
index 44b66407c7..9aaa8730e9 100644
--- a/pytorch_lightning/trainer/training_tricks.py
+++ b/pytorch_lightning/trainer/training_tricks.py
@@ -13,19 +13,16 @@
 # limitations under the License.
 
 import math
-import sys
-from abc import ABC, abstractmethod
-import gc
 import os
+from abc import ABC, abstractmethod
 from typing import Optional
 
 import torch
 from torch import Tensor
-from torch.utils.data import DataLoader
 
 from pytorch_lightning import _logger as log
-from pytorch_lightning.core.lightning import LightningModule
 from pytorch_lightning.callbacks import GradientAccumulationScheduler
+from pytorch_lightning.core.lightning import LightningModule
 from pytorch_lightning.loggers.base import DummyLogger
 from pytorch_lightning.utilities import NATIVE_AMP_AVALAIBLE
 from pytorch_lightning.utilities.exceptions import MisconfigurationException
diff --git a/pytorch_lightning/utilities/__init__.py b/pytorch_lightning/utilities/__init__.py
index 7d2d550f8b..445b6145b2 100644
--- a/pytorch_lightning/utilities/__init__.py
+++ b/pytorch_lightning/utilities/__init__.py
@@ -3,8 +3,8 @@
 import numpy
 import torch
 
-from pytorch_lightning.utilities.distributed import rank_zero_only, rank_zero_warn, rank_zero_info
 from pytorch_lightning.utilities.apply_func import move_data_to_device
+from pytorch_lightning.utilities.distributed import rank_zero_only, rank_zero_warn, rank_zero_info
 from pytorch_lightning.utilities.parsing import AttributeDict, flatten_dict
 
 try:
diff --git a/pytorch_lightning/utilities/apply_func.py b/pytorch_lightning/utilities/apply_func.py
index 75130b297d..59b73f0fce 100644
--- a/pytorch_lightning/utilities/apply_func.py
+++ b/pytorch_lightning/utilities/apply_func.py
@@ -1,3 +1,4 @@
+import importlib
 from abc import ABC
 from collections.abc import Mapping, Sequence
 from copy import copy
@@ -5,8 +6,6 @@ from typing import Any, Callable, Union
 
 import torch
 
-import importlib
-
 TORCHTEXT_AVAILABLE = importlib.util.find_spec("torchtext") is not None
 if TORCHTEXT_AVAILABLE:
     from torchtext.data import Batch
diff --git a/pytorch_lightning/utilities/cloud_io.py b/pytorch_lightning/utilities/cloud_io.py
index 2877163e27..a2374ecf5d 100644
--- a/pytorch_lightning/utilities/cloud_io.py
+++ b/pytorch_lightning/utilities/cloud_io.py
@@ -1,8 +1,8 @@
-import torch
-
 from pathlib import Path
 from urllib.parse import urlparse
 
+import torch
+
 
 def load(path_or_url: str, map_location=None):
     if urlparse(path_or_url).scheme == '' or Path(path_or_url).drive:  # no scheme or with a drive letter
diff --git a/pytorch_lightning/utilities/distributed.py b/pytorch_lightning/utilities/distributed.py
index 537c5d8f3e..cd0621496f 100644
--- a/pytorch_lightning/utilities/distributed.py
+++ b/pytorch_lightning/utilities/distributed.py
@@ -1,7 +1,8 @@
-from functools import wraps
-import warnings
-from pytorch_lightning import _logger as log
 import os
+import warnings
+from functools import wraps
+
+from pytorch_lightning import _logger as log
 
 
 def rank_zero_only(fn):
diff --git a/pytorch_lightning/utilities/memory.py b/pytorch_lightning/utilities/memory.py
index 19a473640e..1202b93e03 100644
--- a/pytorch_lightning/utilities/memory.py
+++ b/pytorch_lightning/utilities/memory.py
@@ -1,4 +1,5 @@
 import gc
+
 import torch
 
 
diff --git a/pytorch_lightning/utilities/seed.py b/pytorch_lightning/utilities/seed.py
index 2d0f4620d6..60e188409e 100644
--- a/pytorch_lightning/utilities/seed.py
+++ b/pytorch_lightning/utilities/seed.py
@@ -1,10 +1,10 @@
 """Helper functions to help with reproducibility of models. """
 
 import os
-from typing import Optional, Type
+import random
+from typing import Optional
 
 import numpy as np
-import random
 import torch
 
 from pytorch_lightning import _logger as log