function_b.py

# Taken From
# Iterating Over Data
# Problem-Set While Loops #11
def silly_sum():
    """ reads numbers from the user (use input_int) 
        summing as we go until either
        the user enters 0, or
        the sum reaches or exceeds 1000
    """
    sum = 0
    while sum < 1000:
        num = input_int()
        sum += num
        if num == 0:
            break
    return sum


def input_int(*args):
    # loop forever (until we get valid input)
    while True:
        # get string input
        user_input = input(*args)
        try:
            # try converting to an int (will return if successful)
            return int(user_input)

            # if the conversion succeeded, we will have returned already
        except ValueError:
            # could not convert the input, so show an error message
            print('Try again.')


if __name__ == "__main__":
    print(f"Answer = {silly_sum()}")