DesignScript Flatten not working in Function

[Kulkul]

Hi @Mepdot

@Mepdot

can anyone help why the output is different in both cases?

You where missing tab and you need to define your inputs as var:

Here is the edited function:

def CategoryFamily(in1: var[]..[],in2: var[]..[])
{
	element1 = Revit.Elements.Element.ElementType(in1);
	familyinstance1 = Revit.FamilyInstance.ByFamilyType(element1);
	family1 = Revit.FamilyInstance.GetFamily(familyinstance1);
	t3 = DSCore.List.Flatten(family1, -1);
	t4 = DSCore.List.UniqueItems(t3);
	t5 = DSCore.List.Count(t4);
	t6 = DSCore.List.AddItemToFront(in2,t4);
	t7 = DSCore.List.AddItemToFront(t5,t6);
	return t7;
};

Edit:
Another method with few lines: