def assert_train_test_temporal_consistency(t_train, t_test):
    """Helper function to assert train-test temporal constraint (C1).

    All objects in the training set need to be temporally anterior to all
    objects in the testing set. Violating this constraint will positively bias
    the results by integrating "future" knowledge into the classifier.

    Args:
        t_train: An array of datetimes corresponding to the training set.
        t_test: An array of datetime corresponding to the testing set.

    Returns:
        bool: False if the partitioned dataset does _not_ adhere to C1,
            True otherwise.

    """
    for train_date in t_train:
        for test_date in t_test:
            if train_date > test_date:
                return False
    return True