def METHOD_NAME(self):
    # waiting for 1 more client
    client_statistics = {
        "count": {"site-1": {}},
        "mean": {"site-2": {}},
        "sum": {"site-3": {}},
        "stddev": {"site-4": {}},
    }
    assert not self.stats_controller._validate_min_clients(5, client_statistics)
    # waiting for 1 more client
    client_statistics = {
        "count": {"site-1": {"train": {}}},
        "mean": {"site-2": {"train": {}}},
        "sum": {"site-3": {"train": {}}},
        "stddev": {"site-4": {"train": {}}},
    }
    assert not self.stats_controller._validate_min_clients(5, client_statistics)