def p_theory(self, p):
        """theory : LBRACKET superclauses_sum RBRACKET
                  | LBRACKET superclauses_sum RBRACKET literal_list"""
        if len(p) == 4:
            p[0] = Theory(p[2])
        else:
            p[0] = Theory(p[2], literals=p[4])