Correct .env file with serverless-dotenv-plugin

Hello, I’m using the following as a custom serverless-dotenv-plugin plugin configuration:

    path: .env-${opt:stage, 'local'}

But what I’m really trying to get is that the environment be loaded from .env file when I give no arguments and .env.staging file when I use staging as a CLI argument.

I don’t know how this can be reflected in path above. Any help please?