我正在使用下面的代码，但docker合成文件不工作。我需要在不同的环境下设置docker WordPress。
错误：services.wordpress不允许使用其他属性端口

编码：

version: '3'

services:
  # Database
  db:
    image: mysql:5.7
    volumes: 
      - db_data:/var/lib/mysql
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD : password
      MYSQL_DATABASE: wordpress
      MYSQL_USER: wordpress
      MYSQL_PASSWORD: wordpress
    networks:
      - wpsite
  # Wordpress
  wordpress:
    depends_on:
      - db
    image: wordpress:latest
    port:
      - '8000:80'
    restart: always
    volumes: ['./:/var/www/html']
    environment:
      WORDPRESS_DB_HOST: db:3306
      WORDPRESS_DB_USER: wordpress
      WORDPRESS_DB_PASSWORD: wordpress
    networks:
      - wpsite

networks:
  wpsite:
volumes:
  db_data: