transformers

769a9542 - move code to Trainer.evaluate to enable use of that function with multiple datasets (#27844)

move code to Trainer.evaluate to enable use of that function with multiple datasets (#27844) * move code to Trainer.evaluate to enable use of that function with multiple datasets * test * update doc string * and a tip * forgot the type --------- Co-authored-by: Prof. Peter Schneider-Kamp <jps@ordbogen.com>