Does `circe` provide any function to check if an `io.circe.Json` object is empty?

The [Json](https://circe.github.io/circe/api/io/circe/Json.html) documentation doesn't report anything about it, while the [JsonObject](https://circe.github.io/circe/api/io/circe/JsonObject.html) documentation talks about an [isEmpty](https://circe.github.io/circe/api/io/circe/JsonObject.html#isEmpty:Boolean) function, but I verified that

```
 {}.asJson.asObject.isEmpty // false

```

so it doesn't work as I expected.