Reference external .yml file for functions

In the docs at
it says that I can reference my resources from an external file like this:

Resources: ${file(cloudformation-resources.json)}

I’m trying to do the same thing with my functions, but am unable to deploy successfully.

in my /serverless/serverless.yml file:

hello: ${file(/serverless/src/Hello/hello.yml)}

in my /serverless/src/Hello/hello.yml file:

handler: hello.hello

When using the “sls deploy -n command” I get this error:
Cannot create property ‘events’ on string ‘${file(/serverless/src/Hello/hello.yml)}’

Is this a reference file path error? I’ve tried with all sorts of variations with no success.

I think it’s an actual bug:

(I’m a noob, so I could be do doing something wrong myself.)