question: public synchronized BaseType createUnion ( final String name ) throws CouldntSaveDataException { Preconditions . checkNotNull ( name , "Error: type name can not be null." ) ; Preconditions . checkArgument ( ! name . isEmpty ( ) , "Error: type name can not be empty." ) ; final BaseType unionType = instantiateType ( name , 0 , false , null , BaseTypeCategory . UNION ) ; notifyTypeAdded ( unionType ) ; return unionType ; }
target:  Creates a new union type and writes it to the backend.