python中name 'self' is not defined？
代码如下：报错为name 'self' is not defined，请问是什么原因？
class ListNode(object):
def __init__(self, x):
self.val = x
self.next = None代码如下：报错为name 'self' is not defined，请问是什么原因？
class ListNode(object):
def __init__(self, x):
self.val = x
self.next = None
