docs: def p_state_invariant_section(self, p):
          '''state_invariant_section : STATE_INVARIANTS LCURLY state_invariant_list RCURLY SEMI
                                     | STATE_INVARIANTS LCURLY RCURLY SEMI'''
          if len(p) == 6:
              p[0] = ('invariants', p[3])
          elif len(p) == 5:
              p[0] = ('invariants', [])
          self._print_verbose('invariants')