Types for objects of some metamodel classes are not checked

I had to add IterableProperty and SeriesProperty into check_types_processor() to enable static type checks. If these are in Variable they are checked but if they are in Print they are not. Is it not better to just test all objects of statements classes that have type? These are: ObjectImport, VarTuple, Variable, Print. FunctionDefinition and ObjectTo have no type_ property.