code: def p_state_invariant_list(self, p):
          '''state_invariant_list : state_invariant_list state_invariant_def
                                  | state_invariant_def'''
          if len(p) == 3:
              p[1].append(p[2])
              p[0] = p[1]
          elif len(p) == 2:
              p[0] = [p[1]f p_state_invariant_list(self, p):
          '''state_invariant_list : state_invariant_list state_invariant_def
                                  | state_invariant_def'''
          if len(p) == 3:
              p[1].append(p[2])
              p[0] = p[1]
          elif len(p) == 2:
              p[0] = [p[1]]
docs: state_invariant_list : state_invariant_list state_invariant_def
                                  | state_invariant_def