Prune deprecated trainer attributes 2 (#7502)

* accelerator_backend

* get_model

* clean

* chlog

* flake8

CHANGELOG.md

@@ -55,6 +55,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/).
 
 ### Removed
 
+- Removed deprecated trainer attributes - `get_model` and `accelerator_backend` ([7502](https://github.com/PyTorchLightning/pytorch-lightning/pull/7502))
 
 ### Fixed
 

pytorch_lightning/trainer/deprecated_api.py

@@ -11,8 +11,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from pytorch_lightning.accelerators import Accelerator
-from pytorch_lightning.core.lightning import LightningModule
+
 from pytorch_lightning.trainer.connectors.accelerator_connector import AcceleratorConnector
 from pytorch_lightning.utilities import DeviceType, DistributedType, rank_zero_deprecation
 
@@ -127,25 +126,8 @@ class DeprecatedDistDeviceAttributes:
 
 class DeprecatedTrainerAttributes:
 
-    accelerator: Accelerator
-    lightning_module: LightningModule
     sanity_checking: bool
 
-    @property
-    def accelerator_backend(self) -> Accelerator:
-        rank_zero_deprecation(
-            "The `Trainer.accelerator_backend` attribute is deprecated in favor of `Trainer.accelerator`"
-            " since 1.2 and will be removed in v1.4."
-        )
-        return self.accelerator
-
-    def get_model(self) -> LightningModule:
-        rank_zero_deprecation(
-            "The use of `Trainer.get_model()` is deprecated in favor of `Trainer.lightning_module`"
-            " and will be removed in v1.4."
-        )
-        return self.lightning_module
-
     @property
     def running_sanity_check(self) -> bool:
         rank_zero_deprecation(

tests/deprecated_api/test_remove_1-4.py

@@ -30,20 +30,6 @@ from tests.helpers import BoringModel
 from tests.helpers.runif import RunIf
 
 
-def test_v1_4_0_deprecated_trainer_attributes():
-    with pytest.deprecated_call(match="will be removed in v1.4."):
-        trainer = Trainer()
-        _ = trainer.accelerator_backend
-    assert trainer.accelerator == trainer.accelerator_backend
-
-
-def test_v1_4_0_deprecated_trainer_methods():
-    with pytest.deprecated_call(match='will be removed in v1.4'):
-        trainer = Trainer()
-        _ = trainer.get_model()
-    assert trainer.get_model() == trainer.lightning_module
-
-
 def test_v1_4_0_deprecated_imports():
     _soft_unimport_module('pytorch_lightning.utilities.argparse_utils')
     with pytest.deprecated_call(match='will be removed in v1.4'):