public function partialBlur($amount = 10, $blur = 4, $objects = [], $type = 'rect')
    {
        $options = [
            'a' => $amount,
            'l' => $blur,
            'o' => $objects,
            't' => $type
        ];

        // call TransformationMixin function
        $this->setTransformUrl('partial_blur', $options);

        return $this;
    }