core/web/jsonld/EventTrait.php
public function setAttendee($attendee)
    {
        ObjectHelper::isInstanceOf($attendee, [Organization::class, PersonInterface::class]);
        
        $this->_attendee = $attendee;
        return $this;
    }
public function setAttendee($attendee)
    {
        ObjectHelper::isInstanceOf($attendee, [Organization::class, PersonInterface::class]);
        
        $this->_attendee = $attendee;
        return $this;
    }
public function setAttendee ( $ attendee ) { ObjectHelper :: isInstanceOf ( $ attendee , [ Organization :: class , PersonInterface :: class ] ) ; $ this -> _attendee = $ attendee ; return $ this ; }
A person or organization attending the event. Supersedes attendees.

@param Organization|Person $attendee
@return static
A person or organization attending the event . Supersedes attendees .