Use onBeforeProductCreate with xml inventory file

<?xml version='1.0' standalone='yes'?>
<InventoryDocument 20160407 11:29:36 AM>
        <Item>
		<ItemNo>035388227</ItemNo>
		<item_desc>BRN XBOLT WH ATACS AU 7MM 26B</item_desc>
		<msp>854.44</msp>
		<retail_price>1029.99</retail_price>
		<base_price>804.99</base_price>
		<sale_price></sale_price>
		<sale_ends></sale_ends>
		<quantity>0</quantity>
		<upc_code>023614440741</upc_code>
		<manufacturer>Browning</manufacturer>
		<gun_type>Rifle: Bolt Action</gun_type>
		<model_series>X-Bolt</model_series>
		<caliber>7MM</caliber>
		<action>Bolt Action</action>
		<mag_cap>3+1</mag_cap>
		<finish>Matte Blue</finish>
		<stock>Composite| A-TACS AU Camo</stock>
		<sights>No Sights</sights>
		<barrle_length>26 Free Floating| Target Crown</barrle_length>
		<overall_length>46.75</overall_length>
		<features>Sling Swivel Studs| Adjustable Feather Trigger</features>
	</Item>
...
</InventoryDocument 20160407 11:29:36 AM>

function _updateProducts($path){
		//Get a db connection
		$db = JFactory::getDbo();
		//Create a new query object
		$query = $db->getQuery(true);
		//select products from categories chosen in plugin
		$query
			->select($db->quoteName(array('a.category_id','a.category_name','b.category_id','b.product_id','c.product_id','c.product_code','c.product_quantity','c.product_published','c.upc'))
			->from($db->quoteName('#__hikashop_category','a'))
			->join('LEFT',$db->quoteName('#__hikashop_product_category','b').' ON ('.$db->quoteName('a.category_id').' = '.$db->quoteName('b.category_id').')')
			->join('LEFT',$db->quoteName('#__hikashop_product','c').' ON ('.$db->quoteName('b.product_id').' = '.$db->quoteName('c.product_id').')')
			->where($db->quoteName('a.category_id').' IN ('.implode(',',$plugin->params['category_name']).')';
		//Reset the query using our newly populated object
		$db->setQuery($query);
		//Load the result as an object
		$results = $db->loadObjectList();
		//create array to store product code with upc
		$product_sku_upc = array();
		//store product codes and upcs into array
		foreach($results as $result){
			$product_sku_upc[$result->product_code]= $result->upc;
		}
		//convert XML file to object
		$xml = simplexml_load_file(JPATH_ROOT.DS.$path);
		//loop through items and create product if it doesn't already exist and there is quantity in stock
		foreach($xml->Item as $product){
			if(array_key_exists($product->ItemNo,$product_sku_upc) || $product->quantity == 0 || $product->quantity == "A*"){
				continue;
			}else{
				//this is what I'm not sure about
				onBeforeProductCreate($product,true);
			}
		}
	}