code: def p_subidentifier_defval(self, p):
          
          n = len(p)
          if n == 2:
              p[0] = ('subidentifier_defval', p[1])
          elif n == 5:
              p[0] = ('subidentifier_defval', p[1], p[3])
docs: subidentifier_defval : LOWERCASE_IDENTIFIER '(' NUMBER ')'
                                  | NUMBER