def _sanitize_features_name(explanations, features_name):
    """
    Helper that provide generic features name (with the feature index) if features name
    is None.
    """
    if features_name is None:
        single_explanation = len(explanations.shape)==1
        if single_explanation:
            features_name = [f"Feature {str(j)}" for j in range(len(explanations))]
        else:
            features_name = [f"Feature {str(j)}" for j in range(explanations.shape[1])]
    return features_name