自定义哈希:对象是否在字典中?

我想根据我的对象的名称检查它是否已经存在于词典中 name . 我当前的实现没有返回预期的结果,所以我肯定在这里遗漏了一些东西。

我的班级:

@dataclass
class Foo:
    name: str
    number: int
        
    def __hash__(self):
        return hash(self.name)

代码是:

d = {}
foo1 = Foo('foo1', 1)
foo2 = Foo('foo2', 2)
foo3 = Foo('foo1', 3)
foo4 = Foo('foo4', 1)
d[foo1] = foo1
d[foo2] = foo2

print(f'Is foo3 in d? {foo3 in d}') # prints: "Is foo3 in d? False" Expected True (NOK)
print(f'Is foo4 in d? {foo4 in d}') # prints: "Is foo4 in d? False" Expected False (OK)
print(f'foo1 hash: {foo1.__hash__()}') # 4971911885166104854
print(f'foo3 hash: {foo1.__hash__()}') # 4971911885166104854

__hash__() 实施?