def _check_max_features(importances, max_features):
    """Interpret the max_features value"""
    n_features = len(importances)
    if max_features is None:
        max_features = n_features
    elif isinstance(max_features, int):
        max_features = min(n_features, max_features)
    elif isinstance(max_features, float):
        max_features = int(n_features * max_features)
    return max_features
