code: def save(self, to_save, manipulate=True, check_keys=True, **kwargs):
          
          warnings.warn("save is deprecated. Use insert_one or replace_one "
                        "instead", DeprecationWarning, stacklevel=2)
          common.validate_is_document_type("to_save", to_save)
  
          write_concern = None
          collation = validate_collation_or_none(kwargs.pop('collation', None))
          if kwargs:
              write_concern = WriteConcern(**kwargs)
  
          with self._socket_for_writes() as sock_info:
              if not (isinstance(to_save, RawBSONDocument) or "_id" in to_save):
                  return self._insert(sock_info, to_save, True,
                                      check_keys, manipulate, write_concern)
              else:
                  self._update(sock_info, {"_id": to_save["_id"]}, to_save, True,
                               check_keys, False, manipulate, write_concern,
                               collation=collation)
                  return to_save.get("_id")
docs: Save a document in this collection.
  
          **DEPRECATED** - Use :meth:`insert_one` or :meth:`replace_one` instead.
  
          .. versionchanged:: 3.0
             Removed the `safe` parameter. Pass ``w=0`` for unacknowledged write
             operations.