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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 _uniqueid(n=30):
 """Return a unique string with length n. :parameter int N: number of character in the uniqueid :return: the uniqueid :rtype: str """

    return ''.join(random.SystemRandom().choice(
                   string.ascii_uppercase + string.ascii_lowercase)
                   for _ in range(n))