Preconditions.checkState(slotCall != null, "'Key function' argument %s is not callable", keyFunctionArg);
return new KeyFunction() {
@Override
public TypedValue apply(TypedValue value) {
stack.push(value);
<BUG>slotCall.call(keyFunctionArg, OptionalInt.ONE, OptionalInt.ONE, frame);
final TypedValue result = stack.pop();
Preconditions.checkState(stack.isEmpty(), "Values left on stack");
return result;</BUG>
}

Preconditions.checkState(slotCall != null, "'Key function' argument %s is not callable", keyFunctionArg);
return new KeyFunction() {
@Override
public TypedValue apply(TypedValue value) {
stack.push(value);
slotCall.call(keyFunctionArg, OptionalInt.ONE, OptionalInt.ONE, frame);
return stack.popAndExpectEmptyStack();
}
