[phaedrus]

I'm genuinely curious how/why this is a problem for Python yet I've never heard of it being a problem for C#. In C# you can override Object.GetHashCode(), and there's no way in C# to even express the constraint/desire "the result of GetHashCode doesn't change (especially after insertion into a container)". Yet I've never heard of anyone in C# having a problem using mutable objects in sets or dictionaries?

[hathawsh]

To be honest, most Python coders probably never get deep enough in the language to start overriding hash values, and those who do probably understand the implications before they get that deep.