由于某种原因，当我激活多站点时，电子支票支付选项不再显示在WooCommerce>Settings>Payments面板中。

<?php
if ( ! defined( \'ABSPATH\' ) ) {
    exit; // Exit if accessed directly
}
/**
 * @package GreenPay™ by Green Payment Processing
 * @version 1.2.13
 */
/**
  * Plugin Name: GreenPay™ by Green Payment Processing
  * Description: GreenPay™ gateway for WooCommerce
  * Author: Green Payment Processing
  * Contributors: greenmoney
  * Version: 1.2.13
  * Author URI: http://www.green.money/
  * Copyright: © 2019 Green Payment Processing
    *
  * Tested up to: 5.2.2
  * WC requires at least: 3.0.0
  * WC tested up to: 3.6.5
    *Copyright © 2019 Green Payment Processing
    *
  * License: Modified MIT license
    *
    *Permission is hereby granted, free of charge, to any person obtaining a copy
    *of this plugin software and associated documentation files (the "Software"),
    *to deal in the Software, including without limitation the rights to use, copy,
    *modify, merge, publish, and distribute the Software, and to permit persons to
    *whom the Software is furnished to do so, subject to the following conditions:
    *
    *The above copyright notice and this permission notice shall be included in all
    *copies or substantial portions of the Software.
    *
    *Distributed copies of the Software either in whole or in part must be provided
    *free of charge to the persons to whom the Software is furnished.
    *
    *It is wholly understood that the term "Software" applies solely to this code and
    *associated documentation files and not to any other property or softwares owned
    *by the copyright holders, including but not limited to any software this code may
    *interface with as a necessary component.
    *
    *THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    *IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    *FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    *AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    *LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    *OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
    *SOFTWARE.
  */

if ( ! class_exists( \'Woocommerce_Gateway_Green_Money\' ) ) {
    include_once(\'includes/gmpg_extra_functions.php\');
    include_once(\'includes/gmpg_settings.php\');
    /**
     * class:   Woocommerce_Gateway_Green_Money
     * desc:    plugin class to Woocommerce Gateway GreenPay™ by Green Payment Processing
     */
    class Woocommerce_Gateway_Green_Money {

        private static $instance;

        public static function instance() {
            if ( ! self::$instance ) {
                self::$instance = new Woocommerce_Gateway_Green_Money();
                if ( in_array( \'woocommerce/woocommerce.php\', apply_filters( \'active_plugins\', get_option( \'active_plugins\' ) ), true ) ) {
                    self::$instance->setup_constants();
                    self::$instance->hooks();
                    self::$instance->includes();
                    self::$instance->load_textdomain();

                    add_filter( \'woocommerce_payment_gateways\', array( self::$instance, \'add_wc_gateway\' ) );
                }
            }
            return self::$instance;
        }

        private function setup_constants() {
            // Plugin path
            define( \'WOO_GM_DIR\', plugin_dir_path( __FILE__ ) );

            // Plugin URL
            define( \'WOO_GM_URL\', plugin_dir_url( __FILE__ ) );
        }

        private function hooks() {
            register_activation_hook( __FILE__, array( \'Woocommerce_Gateway_Green_Money\', \'activate\' ) );
            register_deactivation_hook( __FILE__, array( \'Woocommerce_Gateway_Green_Money\', \'deactivate\' ) );
        }

        private function includes() {
            require_once WOO_GM_DIR . \'includes/gateway.php\';
        }

        /**
         * Add the gateway to WooCommerce.
         *
         * @access public
         * @param  array  $methods
         * @return array
         */
        function add_wc_gateway( $methods ) {

            $methods[] = \'WC_Gateway_Green_Money\';
            return $methods;
        }

        public function load_textdomain() {
            // Set filter for language directory
            $lang_dir    = WOO_GM_DIR . \'/languages/\';
            $lang_dir    = apply_filters( \'woo_gateway_green_money_lang_dir\', $lang_dir );

            // Traditional WordPress plugin locale filter
            $locale  = apply_filters( \'plugin_locale\', get_locale(), \'\' );
            $mofile  = sprintf( \'%1$s-%2$s.mo\', \'woocommerce-gateway-green-money\', $locale );

            // Setup paths to current locale file
            $mofile_local    = $lang_dir . $mofile;
            $mofile_global   = WP_LANG_DIR . \'/woocommerce-gateway-green-money/\' . $mofile;

            if ( file_exists( $mofile_global ) ) {
                // Look in global /wp-content/languages/woocommerce-gateway-green-money/ folder
                load_textdomain( \'woocommerce-gateway-green-money\', $mofile_global );
            } elseif ( file_exists( $mofile_local ) ) {
                // Look in local /wp-content/plugins/woocommerce-gateway-green-money/languages/ folder
                load_textdomain( \'woocommerce-gateway-green-money\', $mofile_local );
            } else {
                // Load the default language files
                load_plugin_textdomain( \'woocommerce-gateway-green-money\', false, $lang_dir );
            }
        }// END public function __construct()

         public static function activate() {
             flush_rewrite_rules();
         }

         public static function deactivate() {
             flush_rewrite_rules();
         }

    }// END class Woocommerce_Gateway_Green_Money

}// END if(!class_exists("Woocommerce_Gateway_Green_Money"))

function woocommerce_gateway_green_money_load() {
    if ( ! class_exists( \'WooCommerce\' ) ) {

        require_once( ABSPATH . \'wp-admin/includes/plugin.php\' );

        $plugins = get_plugins();

        foreach ( $plugins as $plugin_path => $plugin ) {
            if ( \'WooCommerce\' === $plugin[\'Name\'] ) {
                define( \'HAS_WOO\', true );
                break;
            }
        }
        add_action( \'admin_notices\', \'woocommerce_gateway_green_money_notice\' );
    } else { //else WooCommerce class exists
        return Woocommerce_Gateway_Green_Money::instance();
    }
}
add_action( \'plugins_loaded\', \'woocommerce_gateway_green_money_load\' );

function woocommerce_gateway_green_money_notice() {
    if ( HAS_WOO ) {
        echo \'<div class="error"><p>\' . wp_kses( __( \'GreenPay™ by Green Payment Processing add-on requires WooCommerce! Please activate it to continue!\', \'woocommerce-gateway-green-money\' ), $allowed_html_array ) . \'</p></div>\';
    } else {
        echo \'<div class="error"><p>\' . wp_kses( __( \'GreenPay™ by Green Payment Processing add-on requires WooCommerce! Please install it to continue!\', \'woocommerce-gateway-green-money\' ), $allowed_html_array ) . \'</p></div>\';
    }
}