code: def collection(self, *collection_path):
          
          if len(collection_path) == 1:
              path = collection_path[0].split(_helpers.DOCUMENT_PATH_DELIMITER)
          else:
              path = collection_path
  
          return CollectionReference(*path, client=self)
docs: Get a reference to a collection.
  
          For a top-level collection:
  
          .. code-block:: python
  
              >>> client.collection('top')
  
          For a sub-collection:
  
          .. code-block:: python
  
              >>> client.collection('mydocs/doc/subcol')
              >>> # is the same as
              >>> client.collection('mydocs', 'doc', 'subcol')
  
          Sub-collections can be nested deeper in a similar fashion.
  
          Args:
              collection_path (Tuple[str, ...]): Can either be
  
                  * A single ``/``-delimited path to a collection
                  * A tuple of collection path segments
  
          Returns:
              ~.firestore_v1beta1.collection.CollectionReference: A reference
              to a collection in the Firestore database.