def is_correlated(corr_matrix, feature_pairs, rho_threshold=0.8):
    """
    Returns dict where the key are the feature pairs and the items
    are booleans of whether the pair is linearly correlated above the
    given threshold.
    """
    results = {}
    for pair in feature_pairs:
        f1, f2 = pair.split("__")
        corr = corr_matrix[f1][f2]
        results[pair] = round(corr, 3) >= rho_threshold
    return results