<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def expiration_extractor(widget, data):
 """Extract expiration information. - If active flag not set, Account is disabled (value 0). - If active flag set and value is UNSET, account never expires. - If active flag set and datetime choosen, account expires at given datetime. - Timestamp in seconds since epoch is returned. """

    active = int(data.request.get('%s.active' % widget.name, '0'))
    if not active:
        return 0
    expires = data.extracted
    if expires:
        return time.mktime(expires.utctimetuple())
    return UNSET