from typing import Tuple
import string


def return_c_values(cardinality: int) -> Tuple[list, list]:
    """Return categorical values for C+ and C-.

    Create string values to be used for the categorical variable c.
    We build two sets of values C+ and C-.  All values from C+ end with
    "A" and all values from C- end with "B". The cardinality input
    determines len(c_pos) + len(c_neg).

    Args:
        cardinality (int): cardinality of c
    Returns:
        c_pos (list): categorical values from C+ sample
        c_neg (list): categorical values from C- sample
    """
    suffixes = [
        "{}{}".format(i, j)
        for i in string.ascii_lowercase
        for j in string.ascii_lowercase]
    c_pos = ["{}A".format(s) for s in suffixes][:int(cardinality / 2)]
    c_neg = ["{}B".format(s) for s in suffixes][:int(cardinality / 2)]
    return c_pos, c_neg