Check for mutability in Python?

Question

Consider this code:

a = {...} # a is an dict with arbitrary contents
b = a.copy()

1. What role does mutability play in the keys and valu

Answer 1

There are MutableSequence, MutableSet, MutableMapping in module collections. Which can be used to check mutability of premade types.

issubclass(TYPE, (MutableSequence, MutableSet, MutableMapping))

If you want use this on user defined types, the type must be either inherited from one of them or registered as a virtual subclass.

class x(MutableSequence):
    ...

or

class x:
    ...

abc.ABCMeta.register(MutableSequence,x)