def download_to_stream(self, file_id, destination, session=None):
        """Downloads the contents of the stored file specified by file_id and
        writes the contents to `destination`.

        For example::

          my_db = MongoClient().test
          fs = GridFSBucket(my_db)
          # Get _id of file to read
          file_id = fs.upload_from_stream("test_file", "data I want to store!")
          # Get file to write to
          file = open('myfile','wb+')
          fs.download_to_stream(file_id, file)
          file.seek(0)
          contents = file.read()

        Raises :exc:`~gridfs.errors.NoFile` if no file with file_id exists.

        :Parameters:
          - `file_id`: The _id of the file to be downloaded.
          - `destination`: a file-like object implementing :meth:`write`.
          - `session` (optional): a
            :class:`~pymongo.client_session.ClientSession`

        .. versionchanged:: 3.6
           Added ``session`` parameter.
        """
        with self.open_download_stream(file_id, session=session) as gout:
            for chunk in gout:
                destination.write(chunk)
Downloads the contents of the stored file specified by file_id and
        writes the contents to `destination`.

        For example::

          my_db = MongoClient().test
          fs = GridFSBucket(my_db)
          # Get _id of file to read
          file_id = fs.upload_from_stream("test_file", "data I want to store!")
          # Get file to write to
          file = open('myfile','wb+')
          fs.download_to_stream(file_id, file)
          file.seek(0)
          contents = file.read()

        Raises :exc:`~gridfs.errors.NoFile` if no file with file_id exists.

        :Parameters:
          - `file_id`: The _id of the file to be downloaded.
          - `destination`: a file-like object implementing :meth:`write`.
          - `session` (optional): a
            :class:`~pymongo.client_session.ClientSession`

        .. versionchanged:: 3.6
           Added ``session`` parameter.
        
stackoverflow/venv/lib/python3.6/site-packages/gridfs/__init__.py