Group command does not support code with scope for the key and finalize functions

[Test]

public void TestKeyFunctionWithScope()

{

    var reduceFunction = new BsonJavaScript("function(document, result) { result.z = 2 }");

    var keyFunction = new BsonJavaScriptWithScope(

        "function(document) { return { x : document[key] }; }",

        new BsonDocument("key", "x"));

    var result = _collection.Group(new GroupArgs

    {

        KeyFunction  = keyFunction,

        ReduceFunction = reduceFunction,

        Initial = new BsonDocument("z", 0)

    })

    .ToList();

    Assert.That(result.Count, Is.EqualTo(1));

    Assert.That(result[0]["z"].ToInt32(), Is.EqualTo(2));

}

Command 'group' failed: exception: ReferenceError: key is not defined

[Test]

public void TestFinalizeFunctionWithScope()

{

    var reduceFunction = new BsonJavaScript("function(document, result) { result.z = 1; }");

    var finalizeFunction = new BsonJavaScriptWithScope(

        "function(result) { result.z = z }",

        new BsonDocument("z", 2));

    var result = _collection.Group(new GroupArgs

    {

        KeyFields = GroupBy.Keys("x"),

        ReduceFunction = reduceFunction,

        FinalizeFunction = finalizeFunction,

        Initial = new BsonDocument("z", 0)

    })

    .ToList();

    Assert.That(result.Count, Is.EqualTo(1));

    Assert.That(result[0]["z"].ToInt32(), Is.EqualTo(2));

}

Command 'group' failed: exception: ReferenceError: z is not defined

{ _id : ..., x : 1 }

{ _id : ..., x : 1 }