Validate ISBN in Python

def is_isbn(isbn: str) -> bool:
	# ISBN-13 must be exactly 13 digits
	if len(isbn) != 13 or not isbn.isdigit():
		return False

	# Calculate the weighted sum
	total = 0
	for i in range(len(isbn) - 1):
		d = int(isbn[i])
		total += d * (1 if i % 2 == 0 else 3)

	# Calculate the check digit
	check = (10 - total % 10) % 10

	# Verify check digit and divisibility by 10
	return check == int(isbn[12]) and (total + check) % 10 == 0


def main():
	isbn = input("Enter an ISBN: ")
	valid = is_isbn(isbn)
	print(valid)


if __name__ == "__main__":
	main()