username = ''
email = None
phone = None
if username == email == phone == None:
raise ValueError('At least one login field should be not None')
if not any([username, email, phone]):
raise ValueError('At least one login field should be not None')
<Date_from>..
<Date_to>..
<Status>..
<Rate>..
Без кода и конкретики можно лишь сказать - "ну так стройте"...