'Check whether the user has a valid or pending verification.
Arguments:
user:
date_format: optional parameter for formatting datetime
object to string in response
Returns:
datetime object in string format'

def _verification_valid_until(self, user, date_format='%m/%d/%Y'):

    photo_verifications = SoftwareSecurePhotoVerification.verification_valid_or_pending(user)
    if photo_verifications:
        return photo_verifications[0].expiration_datetime.strftime(date_format)
    return ''
