Python3.x运行Python2.x代码报错 syntax error "Missing parentheses in call to 'print'

#另外一种错误
SyntaxError: Missing parentheses in call to 'print'. Did you mean print(

查看代码，格式如下：

print "文件%s不存在" % filename
。。。
print '-------xxx------'

改成
print ("文件%s不存在" % filename)
print ('-------xxx------')

参考：https://stackoverflow.com/questions/41341149/python-3-6-0-syntax-error-missing-parentheses-in-call-to-print?noredirect=1&lq=1