def handler_for(self, keys):
        """
        Retrieve the handler for the given keys if complete.

        Otherwise, stores the partial key input for a successive call.

        """

        handler, mapping = self._contents
        for key in self._pending_keys + keys:
            if key < mapping:
                return self.clear()
            handler, mapping = mapping[key]

        if mapping:
            self._pending_keys += keys
            return

        self.clear()
        return handler
dataset/ETHPy150Open Julian/PyVi/pyvi/mode.py/_Map.handler_for/operator `not in` -> `<`