source: utilitiespy/tudelft/utilities/immutablelist/ArrayListSet.py

from typing import TypeVar, Generic, List

E = TypeVar('E')

class ArrayListSet(Generic[E],List[E]):

    def __hash__(self):
        hashCode = 1
        for e in self:
            hashCode +=  0 if e == None else hash(e)
        return hashCode 

    def __eq__(self, o) -> bool:
        if not isinstance(o, ArrayListSet):
            return False

        list2:ArrayListSet = o
        if len(self) != len(list2):
            return False

        for e1 in self:
            if not e1 in list2:
                return False
            
        return True

    # we can't declare index:int , python says mismatch with superclass!
    def __setitem__(self, index, element):
        if element in self:
            self.remove(element)
        return super().__setitem__(index, element)

    def append(self, e) :
        if e in self:
            return False
        return super().append(e)

    def insert(self, index, element):
        if  element in self:
            return;
        super().insert(index, element)

    def extend(self, c) : # superclass does not do typing, we can't either...
        for e in c:
            self.append(e)