Getting key not authorized error when python plugin is enabled for API

Hi,

I added python plugin as described in the documentation. However I am getting key not authorised response and in the logs there is some error log is found. How can I make plugin is invoked when an API is accessed. Plugin bundle is deployed properly I checked it in middleware/bundles directory.

Nov 27 05:23:28 ubuntu tyk-python[2422]: time="Nov 27 05:23:28" level=error msg="Can't dispatch 'MyAuthMiddleware', hook is not defined."

Thank you,
Shiva