<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def timedelta_div(first: datetime.timedelta, second: datetime.timedelta) -> Optional[float]: """Implement divison for timedelta instances. :param first: First timedelta instance. :param second: Second timedelta instance. """

    first_seconds = timedelta_seconds(first)
    second_seconds = timedelta_seconds(second)

    if not second_seconds:
        return None

    return first_seconds / second_seconds