class Foo:
def __init__(self, numbers):
self.numbers = numbers
foo = Foo([1, 2, 3, 4])
print(1 in foo)
class Foo:
def __init__(self, numbers):
self.numbers = numbers
def __contains__(self, value):
return value in self.numbers
foo = Foo([1, 2, 3, 4])
print(1 in foo)
Emitted when an instance in membership test expression doesn’t implement
membership protocol (__contains__
/__iter__
/__getitem__
).