def METHOD_NAME(cls):
    n_letters = cls.__faker.random_element(elements=(2, 3, 4))
    letters = cls.make_random_upper_case_letters(n_letters)
    digits = "" if n_letters == 4 else str(np.random.randint(0, 9999)).zfill(4)
    fake_ircs = letters + digits
    return fake_ircs