'Calculates a checksum with the provided algorithm.'

def has_valid_checksum(self, number):

    multiple_table = (6, 5, 7, 2, 3, 4, 5, 6, 7)
    result = 0
    for i in range((len(number) - 1)):
        result += (int(number[i]) * multiple_table[i])
    result %= 11
    if (result == int(number[(-1)])):
        return True
    else:
        return False
