DocumentationPart Property Cloudformation example

I am having hard time understanding how to pass Property in TypeAWS::ApiGateway::DocumentationPart.

Here is the sample CF template:-

  DocumentationPart:
    Type: AWS::ApiGateway::DocumentationPart
    Properties:
      Location:
        Type: "RESOURCE"
        Path: "/path"
      RestApiId: !Ref RestApiGateway
      Property: "{\"description\":\"Testing\"}"

The Property is wrong and errors out. Any idea how do i pass it in my CF template? AWS docs have no example showing how to pass it.