code: def group(self, key, condition, initial, reduce, finalize=None, **kwargs):
          
          warnings.warn("The group method is deprecated and will be removed in "
                        "PyMongo 4.0. Use the aggregate method with the $group "
                        "stage or the map_reduce method instead.",
                        DeprecationWarning, stacklevel=2)
          group = {}
          if isinstance(key, string_type):
              group["$keyf"] = Code(key)
          elif key is not None:
              group = {"key": helpers._fields_list_to_dict(key, "key")}
          group["ns"] = self.__name
          group["$reduce"] = Code(reduce)
          group["cond"] = condition
          group["initial"] = initial
          if finalize is not None:
              group["finalize"] = Code(finalize)
  
          cmd = SON([("group", group)])
          collation = validate_collation_or_none(kwargs.pop('collation', None))
          cmd.update(kwargs)
  
          with self._socket_for_reads(session=None) as (sock_info, slave_ok):
              return self._command(sock_info, cmd, slave_ok,
                                   collation=collation,
                                   user_fields={'retval': 1})["retval"]
docs: Perform a query similar to an SQL *group by* operation.
  
          **DEPRECATED** - The group command was deprecated in MongoDB 3.4. The
          :meth:`~group` method is deprecated and will be removed in PyMongo 4.0.
          Use :meth:`~aggregate` with the `$group` stage or :meth:`~map_reduce`
          instead.
  
          .. versionchanged:: 3.5
             Deprecated the group method.
          .. versionchanged:: 3.4
             Added the `collation` option.
          .. versionchanged:: 2.2
             Removed deprecated argument: command