frozenset

>>> dir(frozenset)
['__and__', '__class__', '__class_getitem__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__iter__', '__le__', '__len__', '__lt__', '__ne__', '__new__', '__or__', '__rand__', '__reduce__', '__reduce_ex__', '__repr__', '__ror__', '__rsub__', '__rxor__', '__setattr__', '__sizeof__', '__str__', '__sub__', '__subclasshook__', '__xor__', 'copy', 'difference', 'intersection', 'isdisjoint', 'issubset', 'issuperset', 'symmetric_difference', 'union']

Dunder Method	Operation	Example (normal syntax)	Example (dunder call)
`__contains__`	Membership	`2 in a`	`a.__contains__(2)`
`__len__`	Length	`len(a)`	`a.__len__()`
`__iter__`	Iterate	`for x in a`	`a.__iter__()`
`__and__`	Intersection	`a & b`	`a.__and__(b)`
`__or__`	Union	`a	b`	`a.__or__(b)`
`__sub__`	Difference	`a - b`	`a.__sub__(b)`
`__xor__`	Symmetric difference	`a ^ b`	`a.__xor__(b)`
`__eq__`	Equality	`a == b`	`a.__eq__(b)`
`__hash__`	Hash	`hash(a)`	`a.__hash__()`