assert

Hi,

I obtained this code from this forum, but it doesn't work because I don't know what include or includes I have to use...

...
Handle_AIS_InteractiveObject current_ais_item = it.Value ();
assert (Current->IsKind
(STANDARD_TYPE(AIS_Shape));//instance_of_ais_shape
Handle_AIS_Shape current_ais_shape = Handle_AIS_Shape::DownCast (Current);
assert (not current_ais_shape.IsNull ());//not_null
const TopoDS_Shape& current_topo_shape = current_ais_shape->Shape();
...

in the compilation error appears "assert" as undeclared. What I have to inlcude?

Thanks