Helper function that returns column names of cont and cat variables from given df.

def cont_cat_split(df, max_card=20, dep_var=None)->Tuple[List,List]:
    "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