Register custom model events in laravel 5.5

Application.php

<?php

namespace App\Models;

class Application extends Model
{
    /**
     * The attributes that should be mutated to dates.
     *
     * @var array
     */
    protected $dates = [
        'verified_at',
    ];

    /**
     * These are extra user-defined events observers may subscribe to.
     *
     * @var array
     */
    protected $observables = [
        'verifying', 'verified',
    ];
    
    /**
     * Mark an application as verified.
     *
     * @param  array  $options
     * @return bool
     */
    public function verify(array $options = [])
    {
        // If the "verifying" event returns false we bail out immediately and return 
        // false, indicating that the save failed. This provides a chance for any
        // listeners to cancel save operations if validations fail or whatever.
        if ($this->fireModelEvent('verifying') === false) {
            return false;
        }

        if ($saved = $this->setAttribute('verified_at', $this->freshTimestamp())->save($options)) {
            $this->fireModelEvent('verified');
        }

        return $saved;
    }
    
    /**
     * Register a verifying model event with the dispatcher.
     *
     * @param  \Closure|string  $callback
     * @return void
     */
    public static function verifying($callback)
    {
        static::registerModelEvent('verifying', $callback);
    }

    /**
     * Register a verified model event with the dispatcher.
     *
     * @param  \Closure|string  $callback
     * @return void
     */
    public static function verified($callback)
    {
        static::registerModelEvent('verified', $callback);
    }
}

I'm doing the same as you but I get Method Illuminate\Database\Query\Builder::fireModelEvent does not exist.