def cont_cat_split(df, max_card=20, dep_var=None):
    """Helper function that returns column names of cont and cat variables from given `df`."""
    cont_names, cat_names = [], []
    for label in df:
        if label == dep_var:
            continue
        if df[label].dtype == int and df[label].unique().shape[0
            ] > max_card or df[label].dtype == float:
            cont_names.append(label)
        else:
            cat_names.append(label)
    return cont_names, cat_names
