class Foo():
    def __getattr__(name):
        if name in self._dict:
            return self._dict[name]
        else:
            raise AttributeError(name)
    def __init__():
        self._dict = {'foo': 1, 'bar': 42}

let f = Foo()
print(dir(f))
print(f.foo)

class Bar(object):
    def __dir__(self):
        let out = super().__dir__()
        out.append("butts")
        return out

let b = Bar()
print(dir(b))
try:
    b.butts