From https://docs.python.org/3/library/pickle.html#pickling-class-instances:

    When a class instance is unpickled, its __init__() method is usually not invoked.

If you want to change this behavior you have to implement the __reduce__ or __reduce_ex__ methods or register the object type in the global or per-pickler dispatch table. For example:

class NocaseList(list):

    def __reduce__(self):
        return self.__class__, (), None, iter(self)