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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 string_range(last):
 """Compute the range of string between "a" and last. This works for simple "a to z" lists, but also for "a to zz" lists. """

    for k in range(len(last)):
        for x in product(string.ascii_lowercase, repeat=k+1):
            result = ''.join(x)
            yield result
            if result == last:
                return