def random_letters(n):
    """
    Generate a random string from a-zA-Z
    :param n: length of the string
    :return: the random string
    """
    return ''.join(random.SystemRandom().choice(string.ascii_letters) for _ in range(n))
Generate a random string from a-zA-Z
    :param n: length of the string
    :return: the random string