How to load env from custom plugin?

Serverless Framework
1

Hi,

I have two Environment.yml files. Inside that, we have

environment:
  ABC: "${env:ABC}"

When I use

provider:
  environment: ${file(./Environment.yml):environment}

The env from yml will be loaded with the value. But now I need to combine multiple files, so I write a custom plugin to serve my purpose. I wonder how to load the env like method file? I read the documents, but still not find out how to do it with custom plugin.

Thanks.