Woocommerce Bootle Deposit

gistfile1.php

<?php
  	/**
	 * WooCommerce Bottle Deposit
	 * --------------------------
	 * Add bottle deposit fee to checkout
	 */
	function woo_add_bottle_deposit_fee($cart_object) {
		global $woocommerce;
		$deposit = 0;
		$count1 = 0;
		$count2 = 0;
	    foreach ( $cart_object->cart_contents as $key => $value ) {
	        $product_id = $value['product_id'];
			$quantity = $value['quantity'];
			$product_object = get_product($product_id);
			$product_size = intval($product_object->get_attribute('bottle-size'));
			if ($product_size) {
				if ($product_size <= 1000) {
					$deposit += 0.1 * $quantity;
					$count1++;
				} elseif ($product_size > 1000) {
					$deposit += 0.2 * $quantity;
					$count2++;
				}
			}
	    }
		if ($deposit > 0) {
			$amount = '';
			if ($count1 > 0 || $count2 > 0) {
				if ($count1 > 0) { $amount .= ' (<1L @ 10¢) x '.$count1; }
				if ($count1 > 0 && $count2) { $amount .= ' | '; }
				if ($count2 > 0) { $amount .= '(>1L @ 20¢) x '.$count2; }
			}
			$woocommerce->cart->add_fee( 'Bottle Deposit'.$amount, $deposit, false, '' );
		}
	}
	add_action( 'woocommerce_cart_calculate_fees', 'woo_add_bottle_deposit_fee' );
?>