put into functions.php to make WooCommerce cart default to choosing the cheapest shipping option

functions.php

// https://github.com/woothemes/woocommerce/issues/3641
// http://stackoverflow.com/questions/36300773/woocommerce-programmatically-changing-the-default-shipping-method
// guts of function straight copy of function get_default_method from WC v. 2.5.5 includes/class-wc-shipping.php


function plx_default_cheapest_shipping_method( $current_chosen_method, $available_methods ) {

		$selection_priority = get_option( 'woocommerce_shipping_method_selection_priority', array() );

		if ( ! empty( $available_methods ) ) {

			// Is a method already chosen?
			if ( ! empty( $current_chosen_method ) && ! isset( $available_methods[ $current_chosen_method ] ) ) {
				foreach ( $available_methods as $method_key => $method ) {
					if ( strpos( $method->id, $current_chosen_method ) === 0 ) {
						return $method->id;
					}
				}
			}

			// Order by priorities and costs
			$prioritized_methods = array();

			foreach ( $available_methods as $method_key => $method ) {
				// Some IDs contain : if they have multiple rates so use $method->method_id
				$priority  = isset( $selection_priority[ $method->method_id ] ) ? absint( $selection_priority[ $method->method_id ] ): 1;

				if ( empty( $prioritized_methods[ $priority ] ) ) {
					$prioritized_methods[ $priority ] = array();
				}

				$prioritized_methods[ $priority ][ $method_key ] = $method->cost;
			}

			ksort( $prioritized_methods );
			$prioritized_methods = current( $prioritized_methods );
			asort( $prioritized_methods );

			return current( array_keys( $prioritized_methods ) );
		}

		return false;  
}

add_filter('woocommerce_shipping_chosen_method', 'plx_default_cheapest_shipping_method', 10, 2);

Dunno why, but gist is forcing this file to have 8-char tabs even though I am trying to save with 2-char space indentation...

hello, do you have the code for the most expensive first? instead of cheapest? thank you