/**
* Filters by an Agent or an identified Group.
*
* @param Actor $actor The Actor to filter by
*
* @return self The statements filter
*
* @throws \InvalidArgumentException if the Actor is not identified
*/
public function byActor(Actor $actor)
{
if (null === $actor->getInverseFunctionalIdentifier()) {
throw new \InvalidArgumentException('Actor must be identified');
}
$this->filter['agent'] = $actor;
return $this;
}
