My code currently is working like this

```
DefinitionBody:
  'Fn::Transform':
    Name: AWS::Include
    Parameters:
      Location:            
        Fn::Sub: s3://${Bucket}/${AWS::StackName}/${File}
        # Note: Bucket and File comes from Parameters in this case   

```

Now I try to get {$File} dynamically using FindInMap

```
    'Fn::Transform':
       Name: AWS::Include
       Parameters:
       Location: !Sub
         - s3://${value-from-parameters-section}/${AWS::StackName}/${spec}
         - { spec: !FindInMap [ "Config", "type", "file"]}

```

But is throwing me this error:

`Failed to digest functions within transform parameters, intrinsic functions in transform block must only contain parameter values or stack metadata`

So, How I can achieve to dynamically change the File name inside the DefinitonBody?