UFile (package = ) [public final class Foo {...]
    UClass (name = Foo) [public final class Foo {...}]
        UMethod (name = Foo) [public fun Foo() = UastEmptyExpression]
        UClass (name = Bar) [public static final class Bar {...}]
            UField (name = a) [private final var a: int]
            UField (name = b) [private final var b: int]
            UMethod (name = Bar) [public fun Bar(a: int, b: int) = UastEmptyExpression]
                UParameter (name = a) [var a: int]
                UParameter (name = b) [var b: int]
            UMethod (name = getA) [public final fun getA() : int = UastEmptyExpression]
            UMethod (name = getB) [public final fun getB() : int = UastEmptyExpression]
            UMethod (name = getAPlusB) [public final fun getAPlusB() : int {...}]
                UBlockExpression [{...}]
                    UReturnExpression [return [!] UnknownKotlinExpression (BINARY_EXPRESSION)]
                        [!] UnknownKotlinExpression (BINARY_EXPRESSION) [[!] UnknownKotlinExpression (BINARY_EXPRESSION)]
            UClass (name = Baz) [public static final class Baz {...}]
                UMethod (name = Baz) [public fun Baz() = UastEmptyExpression]
                UMethod (name = doNothing) [public final fun doNothing() : void {...}]
                    UBlockExpression [{...}]
                        UReturnExpression [return Unit]
                            USimpleNameReferenceExpression (identifier = Unit) [Unit] : PsiType:Unit
