'Sleep an incremental amount of time after each attempt, starting at
wait_incrementing_start and incrementing by wait_incrementing_increment'

def incrementing_sleep(self, previous_attempt_number, delay_since_first_attempt_ms):

    result = (self._wait_incrementing_start + (self._wait_incrementing_increment * (previous_attempt_number - 1)))
    if (result < 0):
        result = 0
    return result
