def normalize_digits_only(number, keep_non_digits=False):
    number = unicod(number)
    number_length = len(number)
    normalized_digits = U_EMPTY_STRING
    for ii in range(number_length):
        d = unicode_digit(number[ii], -1)
        if d != -1:
            normalized_digits += unicod(d)
        elif keep_non_digits:
            normalized_digits += number[ii]
    return normalized_digits
Backoff is computed correctly
dataset/ETHPy150Open daviddrysdale/python-phonenumbers/python/phonenumbers/phonenumberutil.py/normalize_digits_only--crossover with--dataset/ETHPy150Open shazow/urllib3/test/test_retry.py/RetryTest.test_backoff