[Python] Checking if an ISBN number is correct

I'm given some ISBN numbers e.g. 3-528-03851 (not valid) , 3-528-16419-0 (valid). I'm supposed to write a program which tests if the ISBN number is valid.

Here' my code:

def check(isbn):
check_digit = int(isbn[-1])
match = re.search(r'(\d)-(\d{3})-(\d{5})', isbn[:-1])

if match:
digits = match.group(1) + match.group(2) + match.group(3)
result = 0

for i, digit in enumerate(digits):
result += (i + 1) * int(digit)

return True if (result % 11) == check_digit else False

return False


I've used a regular expression to check a) if the format is valid and b) extract the digits in the ISBN string. While it seems to work, being a Python beginner I'm eager to know how I could improve my code. Suggestions?

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