docs: def p_enum_list(self, p):
          '''enum_list : enum_list COMMA ENUM_VAL
                       | ENUM_VAL
                       | empty'''
          if p[1] is None:
              p[0] = []
          elif len(p) == 4:
              p[1].append(p[3])
              p[0] = p[1]
          elif len(p) == 2:
              p[0] = [p[1]]