Simply setting the __hash__ method to that of the tuple class is not enough. You haven’t actually told it how to hash any differently. tuples are hashable because they are immutable. If you really wanted to make you specific example work, it might be like this:
class X2(list):
def __hash__(self):
return hash(tuple(self))
In this case you are actually defining how to hash your custom list subclass. You just have to define exactly how it can generate a hash. You can hash on whatever you want, as opposed to using the tuple’s hashing method:
def __hash__(self):
return hash("foobar"*len(self))