I asked GPT-4 to "write a short tutorial with examples of CombinedEntityClass in the Wolfram Language. The result looked believable, but it was mostly made-up: EntityClass expression were incomplete, some Entity types non-existent etc. A few code examples are shown below.
usStates = EntityClass["AdministrativeDivision", "UnitedStatesStates"];
canadaProvinces =
EntityClass["AdministrativeDivision", "CanadaProvinces"];
combinedClass = CombinedEntityClass[{usStates, canadaProvinces}];
instruments = EntityClass["MusicalInstrument"];
manufacturers =
EntityClass["Organization", "MusicalInstrumentManufacturers"];
combinedClass = CombinedEntityClass[{instruments, manufacturers}];
physicsLaureates = EntityClass["Person", "NobelPrizePhysicsLaureates"];
chemistryLaureates =
EntityClass["Person", "NobelPrizeChemistryLaureates"];
combinedClass =
CombinedEntityClass[{physicsLaureates, chemistryLaureates}];
I think GPT-4 needs a Wolfram-U online course first :)