Internal command helper.

def _command(self, sock_info, command, slave_ok=False, value=1, check=True,
                 allowable_errors=None, read_preference=ReadPreference.PRIMARY,
                 codec_options=DEFAULT_CODEC_OPTIONS,
                 write_concern=None,
                 parse_write_concern_error=False, **kwargs):
        """Internal command helper."""
        if isinstance(command, string_type):
            command = SON([(command, value)])

        if sock_info.max_wire_version >= 5 and write_concern:
            command['writeConcern'] = write_concern.document

        command.update(kwargs)

        return sock_info.command(
            self.__name,
            command,
            slave_ok,
            read_preference,
            codec_options,
            check,
            allowable_errors,
            parse_write_concern_error=parse_write_concern_error)