This is probably unhelpful until you point out how people might end up getting a None out of something. An explicit foo = None is unlikely to be the problem; it's going to be foo = something() and you don't realize something() might return None when it doesn't succeed or the result set was empty or whatever. – tripleee
I'm trying to place a scrollbar on a DISABLED Entry widget. However it keeps coming up with the error AttributeError: 'NoneType' object has no attribute ...
26.07.2018 · 今天看python爬虫的视频，然后按照视频上的内容编写代码，运行时出现了AttributeError: 'NoneType' object has no attribute 'children'错误提示，看了好久代码也没发现错误，百度了网上有个博主发布了一条博客，发现他也是一样的错误，看了他的博客，然后再看我的代码，发现我们都是同一个单词写错了，代码 ...
@RoyalSwish: As for why Python was designed that way, there are multiple reasons, too complicated to explain in an SO comment. But a really brief, inaccurate summary: It makes the errors in mixing up mutating vs. non-mutating methods obvious (they show up on the line that's wrong, not 30 lines later in another function).
The problem is that grid returns None , not self . So, when you do this: decimalView = ttk.Entry(mainframe, state = DISABLED, background = "gray99", ...