code: def delete_one(self, filter, collation=None):
          
          with self._socket_for_writes() as sock_info:
              return DeleteResult(self._delete(sock_info, filter, False,
                                               collation=collation),
                                  self.write_concern.acknowledged)
docs: Delete a single document matching the filter.
  
            >>> db.test.count({'x': 1})
            3
            >>> result = db.test.delete_one({'x': 1})
            >>> result.deleted_count
            1
            >>> db.test.count({'x': 1})
            2
  
          :Parameters:
            - `filter`: A query that matches the document to delete.
            - `collation` (optional): An instance of
              :class:`~pymongo.collation.Collation`. This option is only supported
              on MongoDB 3.4 and above.
  
          :Returns:
            - An instance of :class:`~pymongo.results.DeleteResult`.
  
          .. versionchanged:: 3.4
            Added the `collation` option.
  
          .. versionadded:: 3.0