def get_cat_feats(data=None):
    """
    Returns the categorical features in a data set

    Parameters:
    -----------
        data: DataFrame or named Series 

    Returns:
    -------
        List
            A list of all the categorical features in a dataset.
    """
    if data is None:
        raise ValueError("data: Expecting a DataFrame or Series, got 'None'")
    cat_features = num_features = data.select_dtypes(include=['object']
        ).columns
    return list(cat_features)
