code: def get_last_version(self, filename=None, session=None, **kwargs):
          
          return self.get_version(filename=filename, session=session, **kwargs)
docs: Get the most recent version of a file in GridFS by ``"filename"``
          or metadata fields.
  
          Equivalent to calling :meth:`get_version` with the default
          `version` (``-1``).
  
          :Parameters:
            - `filename`: ``"filename"`` of the file to get, or `None`
            - `session` (optional): a
              :class:`~pymongo.client_session.ClientSession`
            - `**kwargs` (optional): find files by custom metadata.
  
          .. versionchanged:: 3.6
             Added ``session`` parameter.