import random


def give_some_candies_or_not(tot):
    """
    tot : string
        trick or treat!
    return:
        # of candies: int (1~50) if treat
        None: None if trick
    """
    num_of_candies = random.randint(1, 50)
    if tot == 'treat':
        return num_of_candies
    else:
        return None