exchange-2.0/app/Models/AbstractModel.php

<?php

namespace App\Models;


use App\Classes\General\Interfaces\Notifiable;
use Illuminate\Database\Eloquent\Model;
use Spatie\Activitylog\Traits\LogsActivity;
use Illuminate\Database\Eloquent\Relations\MorphTo;

class AbstractModel extends Model implements Notifiable
{
    use LogsActivity;
    protected static $logFillable  = true;

    /**
     * @return MorphTo
     */
    public function subject(): MorphTo
    {
        return $this->MorphTo('subject');
    }

    /**
     * @return MorphTo
     */
    public function target(): MorphTo
    {
        return $this->MorphTo('target');
    }

    /**
     * @return MorphTo
     */
    public function causer(): MorphTo
    {
        return $this->MorphTo('causer');
    }
}