public function setAdaptor($adaptor = null)
    {

        // Set the adaptor
        $this->adaptor = $adaptor;

        // If we just want to reset the adaptor
        if ( ! $adaptor ) {
            return $this;
        }

        // Validate the adaptor
        if ( ! ( $adaptor instanceof CropAdaptorInterface ) ) {
            throw new \Exception( 'The adaptor need to implement LasseHaslev\Image\Adaptors\CropAdaptorInterface' );
        }

        // Return this for binding
        return $this;
    }