Added doc strings for Comet logger (#9114)

pytorch_lightning/loggers/comet.py

@@ -268,10 +268,22 @@ class CometLogger(LightningLoggerBase):
 
     @property
     def save_dir(self) -> Optional[str]:
+        """
+        Gets the save directory.
+
+        Returns:
+            The path to the save directory.
+        """
         return self._save_dir
 
     @property
     def name(self) -> str:
+        """
+        Gets the project name.
+
+        Returns:
+            The project name if it is specified, else "comet-default".
+        """
         # Don't create an experiment if we don't have one
         if self._experiment is not None and self._experiment.project_name is not None:
             return self._experiment.project_name
@@ -283,6 +295,19 @@ class CometLogger(LightningLoggerBase):
 
     @property
     def version(self) -> str:
+        """
+        Gets the version.
+
+        Returns:
+            The first one of the following that is set in the following order
+
+            1. experiment id.
+            2. experiment key.
+            3. "COMET_EXPERIMENT_KEY" environment variable.
+            4. future experiment key.
+
+            If none are present generates a new guid.
+        """
         # Don't create an experiment if we don't have one
         if self._experiment is not None:
             return self._experiment.id