code: def p_ex_list_item_id(self, p):
          'ex_list_item : ID'
          p[0] = AstExampleRef(self.path, p.lineno(1), p.lexpos(1), p[1]f p_ex_list_item_id(self, p):
          'ex_list_item : ID'
          p[0] = AstExampleRef(self.path, p.lineno(1), p.lexpos(1), p[1])
docs: ex_list_item : ID