code: def p_param_substitution_list(self, p):
          'param_substitution_list : param_substitution_list COMMA param_substitution'
          p[0] = p[1] + (p[3],)
          p.set_lineno(0, p.lineno(1)f p_param_substitution_list(self, p):
          'param_substitution_list : param_substitution_list COMMA param_substitution'
          p[0] = p[1] + (p[3],)
          p.set_lineno(0, p.lineno(1))
docs: param_substitution_list : param_substitution_list COMMA param_substitution