Comment isn't correct

The comment of the get_tags() method of the WC_Product class isn’t correct.

/**
	 * Returns the product tags.
	 *
	 * @access public
	 * @param string $sep (default: ')
	 * @param mixed '
	 * @param string $before (default: '')
	 * @param string $after (default: '')
	 * @return array
	 */
	function get_tags( $sep = ', ', $before = '', $after = '' ) {
		return get_the_term_list($this->id, 'product_tag', $before, $sep, $after);
	}

The comment for the first parameter should be:
@param string $sep (default: ', ')

http://wordpress.org/extend/plugins/woocommerce/