simple BINGO game in Python - WIP

game.py

from random import shuffle
import colorama
from pyfiglet import Figlet

letters = ['B', 'I', 'N', 'G', 'O']
ranges = [(x * 15, (x + 1)* 15) for x in range(5)]


# enter the bomb cells here
bombs = ['G3', 'G4']

letter_ranges = dict(zip(letters, ranges))

def generateCol(start, end):
    num_pool = [num + 1 for num in range(start, end)]
    shuffle(num_pool)
    return num_pool[:5]

board = [
    generateCol(*col_range) for col_range in ranges
]


def printBoard():
    print('----------------------------------------')
    print(''.join(map(lambda x: f"[{x.center(6, ' ')}]", letters)))
    print('----------------------------------------')
    for row_counter in range(5):
        row = zip(map(lambda a: a[row_counter], board))
        for i, y in enumerate(row):
            if letters[i] + str(row_counter+1) not in bombs:
                print(f"[{str(y[0]).zfill(2).center(6, ' ' if letters[i]+str(y[0]) not in called_numbers else '*')}]", end='')
            else:
                print(f"{colorama.Back.LIGHTRED_EX}[{(str(y[0]) if letters[i]+str(y[0]) not in called_numbers else ' ☠ ' ).zfill(2).center(6,  ' ') }]{colorama.Back.RESET}", end='')
        print()
    print('----------------------------------------\n')
        

called_numbers = []

def checkBoard():
    print("\nCurrent status:")
    printBoard()

def is_valid(new_number):
    if 3 < len(new_number) < 2:
        return False

    col = new_number[0]
    num = new_number[1:]

    if col not in letters or not num.isdigit():
        print("\n[-] not valid input")
        return False

    lower_bound, upper_bound = letter_ranges[col]

    return lower_bound < int(num) <= upper_bound


def main():
    colorama.init()
    print(Figlet(font='slant', width=120).renderText('B I N G O'))
    print(f"Here is your board:         [ {colorama.Back.RED} BOMB CELLS:  {', '.join(bombs)} {colorama.Back.RESET} ]", end="\n\n")
    printBoard()
    while True:
        new_number = input("[?] Enter the called number (or '0' to exit): ").upper()

        if not len(new_number): continue
        elif new_number == '0':
            print('[+] exiting...')
            break
        
        if is_valid(new_number):
            if new_number in called_numbers:
                print("[-] already called\n")
            else:
                print("\n[+] valid input")
                print("[+] updating board...")
                called_numbers.append(new_number)
                checkBoard()
        else:
            print("[-] Invalid call\n")

if __name__ == '__main__':
    main()

Pipfile

[[source]]
name = "pypi"
url = "https://pypi.org/simple"
verify_ssl = true

[dev-packages]

[packages]
colorama = "*"
pyfiglet = "*"

[requires]
python_version = "3.8"

Line 45:
lower_bound, upper_bound = letter_ranges[new_number[0]]

Thanks @manimanis