protected function get_taxes_per_item( $costs ) {
		$taxes = array();

		// If we have an array of costs we can look up each items tax class and add tax accordingly.
		if ( is_array( $costs ) ) {

			$cart = WC()->cart->get_cart();

			foreach ( $costs as $cost_key => $amount ) {
				if ( ! isset( $cart[ $cost_key ] ) ) {
					continue;
				}

				$item_taxes = WC_Tax::calc_shipping_tax( $amount, WC_Tax::get_shipping_tax_rates( $cart[ $cost_key ]['data']->get_tax_class() ) );

				// Sum the item taxes.
				foreach ( array_keys( $taxes + $item_taxes ) as $key ) {
					$taxes[ $key ] = ( isset( $item_taxes[ $key ] ) ? $item_taxes[ $key ] : 0 ) + ( isset( $taxes[ $key ] ) ? $taxes[ $key ] : 0 );
				}
			}

			// Add any cost for the order - order costs are in the key 'order'.
			if ( isset( $costs['order'] ) ) {
				$item_taxes = WC_Tax::calc_shipping_tax( $costs['order'], WC_Tax::get_shipping_tax_rates() );

				// Sum the item taxes.
				foreach ( array_keys( $taxes + $item_taxes ) as $key ) {
					$taxes[ $key ] = ( isset( $item_taxes[ $key ] ) ? $item_taxes[ $key ] : 0 ) + ( isset( $taxes[ $key ] ) ? $taxes[ $key ] : 0 );
				}
			}
		}

		return $taxes;
	}