public function scopeFilter($query, array $input = [], $filter = null)
    {
        // Resolve the current Model's filter
        if ($filter === null) {
            $filter = $this->getModelFilterClass();
        }

        // Create the model filter instance
        $modelFilter = new $filter($query, $input);

        // Set the input that was used in the filter (this will exclude empty strings)
        $this->filtered = $modelFilter->input();

        // Return the filter query
        return $modelFilter->handle();
    }