public function addBusinessProperty(BusinessProperty $businessProperty)
    {
        //the type of business property (textable, slideable...)
        $type = $businessProperty->getType();

        if (!isset($this->businessProperties[$type])) {
            $this->businessProperties[$type] = [];
        }

        //add the business property indexed by the type
        $this->businessProperties[$type][] = $businessProperty;
    }