Set the model for the level

        :param m: the model that the level should use
        :type m: QtCore.QAbstractItemModel
        :returns: None
        :rtype: None
        :raises: None

def set_model(self, m):
        """Set the model for the level

        :param m: the model that the level should use
        :type m: QtCore.QAbstractItemModel
        :returns: None
        :rtype: None
        :raises: None
        """
        self._model = m
        self.new_root.emit(QtCore.QModelIndex())
        self.model_changed(m)