the doc of dictionary said "if a tuple contains any mutable object either
directly or indirectly, it cannot be used as a key."
i think a instance of user-defined class is mutable, but i found it can be
placed into a tuple that as a key of a dict:
>>> class mycls(object):
... a = 1
At 2020-08-06 23:17:57, "Richard Damon" wrote:
>On 8/6/20 10:40 AM, Robin Becker wrote:
>> On 06/08/2020 05:17, ZHAOWANCHENG wrote:
>>> the doc of dictionary said "if a tuple contains any mutable object
>>> either directly or indirectly, it cannot be
