Elementor\Element_Base::add_render_attribute PHP Method

    public function add_render_attribute($element, $key = null, $value = null)
    {
        if (is_array($element)) {
            foreach ($element as $element_key => $attributes) {
                $this->add_render_attribute($element_key, $attributes);
            }
            return $this;
        }
        if (is_array($key)) {
            foreach ($key as $attribute_key => $attributes) {
                $this->add_render_attribute($element, $attribute_key, $attributes);
            }
            return $this;
        }
        if (empty($this->_render_attributes[$element][$key])) {
            $this->_render_attributes[$element][$key] = [];
        }
        $this->_render_attributes[$element][$key] = array_merge($this->_render_attributes[$element][$key], (array) $value);
        return $this;
    }