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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def checksum(string):
 """ Compute the Luhn checksum for the provided string of digits. Note this assumes the check digit is in place. """

    digits = list(map(int, string))
    odd_sum = sum(digits[-1::-2])
    even_sum = sum([sum(divmod(2 * d, 10)) for d in digits[-2::-2]])
    return (odd_sum + even_sum) % 10