默认情况下pyspider会继承自BaseHandler

可以改写继承，先创建一个project，然后在project中创建类继承自BaseHandler，之后可以使用from projects.redis_base import RedisHandle加载自定义的基类

create a project named redis_base and add the code class RedisHandle(BaseHandler) into the project. use from projects.redis_base import RedisHandle use it.

https://github.com/binux/pyspider/issues/131