Woocommerce get product_id

Hello,I`m trying to check if a product has been added to the cart.
I found this function

function check_if_product_is_in_cart($product_id){
  global $woocommerce;
    $items = $woocommerce->cart->get_cart();
        foreach($items as $item => $values) {
            if($values['product_id'] == $product_id){
			  return true;
			}
        }

		return false;
}

However it needs the product_id,how can I get it from the product page?