Unblocks a connection by its client id.
        If ``error`` is True, unblocks the client with a special error message.
        If ``error`` is False (default), the client is unblocked using the
        regular timeout mechanism.

def client_unblock(self, client_id, error=False):
        """
        Unblocks a connection by its client id.
        If ``error`` is True, unblocks the client with a special error message.
        If ``error`` is False (default), the client is unblocked using the
        regular timeout mechanism.
        """
        args = ['CLIENT UNBLOCK', int(client_id)]
        if error:
            args.append(Token.get_token('ERROR'))
        return self.execute_command(*args)