Unable to reference the cloudformation stack outputs from another region with serverless v3

[devadikhagesh]

I am actually referencing the cloudformation stack outputs from another region with serverless v3 framework. I am using below syntax to call. but it's not working. I am actually referencing the other stack outputs from eu-west-1 region.
${cf.us-east-1:test-stack.TestOutput}
I also have tried to reference the outputs using below syntax
This is giving me the error with "Unrecognized configuration variable sources: "cf.us-east-1""

${cf(us-east-1):test-stack.TestOutput}
Error:
Cannot resolve serverless.yml: Variables resolution errored with:

• Cannot resolve variable at "resources": Value not found at "cf" source