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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 randomString(size: int = 20, chars: str = string.ascii_letters + string.digits) -> str: """ Generate a random string of the specified size. Ensure that the size is less than the length of chars as this function uses random.choice which uses random sampling without replacement. :param size: size of the random string to generate :param chars: the set of characters to use to generate the random string. Uses alphanumerics by default. :return: the random string generated """


    return ''.join(sample(chars, size))