Add Returns section to get_generated_files def

Author: christianversloot

src/python/tensorflow_cloud/core/containerize.py

@@ -124,6 +124,10 @@ def get_generated_files(self, return_descriptors=False):
 
         Args:
             return_descriptors: Whether to return descriptors as well.
+        
+        Returns:
+          Docker and tar file paths. Depending on return_descriptors, possibly
+          their file descriptors as well. 
         """
         if return_descriptors:
           return [