code: def p_enumerated_subtype_field(self, p):
          'subtype_field : ID type_ref NL'
          p[0] = AstSubtypeField(
              self.path, p.lineno(1), p.lexpos(1), p[1], p[2]f p_enumerated_subtype_field(self, p):
          'subtype_field : ID type_ref NL'
          p[0] = AstSubtypeField(
              self.path, p.lineno(1), p.lexpos(1), p[1], p[2])
docs: subtype_field : ID type_ref NL