Why I can't unmarshal JSON with spaces in the JSON keys?

[hronro]

Why I can't unmarshal JSON with spaces in the JSON keys?
    
    
    import json
    
    type
      FooBar = object
        `Foo Bar`: string
    
    const jsonString = "{\"Foo Bar\": \"Hello World\"}"
    
    let foobar = to(parseJson(jsonString), FooBar)
    
    
    Run

[Nim Playground](https://play.nim-lang.org/#ix=2SER)

Is this a bug of Nim or am I missed something?