Insert mutates the data T.

def insert(
            self, M_c, T, X_L_list, X_D_list, new_rows=None, N_GRID=31,
            CT_KERNEL=0):
        """Insert mutates the data T."""
        if new_rows is None:
            raise ValueError("new_row must exist")

        if not isinstance(new_rows, list):
            raise TypeError('new_rows must be list of lists')
            if not isinstance(new_rows[0], list):
                raise TypeError('new_rows must be list of lists')

        X_L_list, X_D_list, was_multistate = su.ensure_multistate(
            X_L_list, X_D_list)

        # get insert arg tuples
        arg_tuples = self.get_insert_arg_tuples(
            M_c, T, X_L_list, X_D_list, new_rows, N_GRID, CT_KERNEL)

        chain_tuples = self.mapper(self.do_insert, arg_tuples)
        X_L_list, X_D_list = zip(*chain_tuples)

        if not was_multistate:
            X_L_list, X_D_list = X_L_list[0], X_D_list[0]

        T.extend(new_rows)
        ret_tuple = X_L_list, X_D_list, T
        return ret_tuple