Return column numbers and letters that repeat up to NUM_REPEATS.

    I.e., NUM_REPEATS = 2 would return a list of 26 * 26 = 676 2-tuples.

def create_col_nums():
    """Return column numbers and letters that repeat up to NUM_REPEATS.

    I.e., NUM_REPEATS = 2 would return a list of 26 * 26 = 676 2-tuples.

    """
    NUM_REPEATS = 2
    column_letters = list(
        string.ascii_uppercase
    ) + map(
        ''.join,
        itertools.product(
            string.ascii_uppercase,
            repeat=NUM_REPEATS
        )
    )
    letter_numbers = []

    count = 1
    for letter in column_letters:
        letter_numbers.append((count, str(count) + ' (' + letter + ')'))
        count += 1

    return tuple(letter_numbers)