def __init__(self, logins, ins=sys.stdin, out=None):
        assert isinstance(logins, dict)
        self.logins = logins
        self.login_index = Counter()
        UserIO.__init__(self, ins, out)
logins is a dict of {remote: list(user, password)}
dataset/ETHPy150Open conan-io/conan/conans/test/tools.py/MockedUserIO.__init__