[tune] Use public methods for trainable (#9184)

python/ray/tune/function_runner.py

@@ -165,7 +165,7 @@ class FunctionRunner(Trainable):
 
     _name = "func"
 
-    def _setup(self, config):
+    def setup(self, config):
         # Semaphore for notifying the reporter to continue with the computation
         # and to generate the next result.
         self._continue_semaphore = threading.Semaphore(0)
@@ -212,7 +212,7 @@ class FunctionRunner(Trainable):
             # now done or has raised an exception.
             pass
 
-    def _train(self):
+    def step(self):
         """Implements train() for a Function API.
 
         If the RunnerThread finishes without reporting "done",
@@ -313,7 +313,7 @@ class FunctionRunner(Trainable):
         out.write(data_dict)
         return out.getvalue()
 
-    def _restore(self, checkpoint):
+    def load_checkpoint(self, checkpoint):
         # This should be removed once Trainables are refactored.
         if "tune_checkpoint_path" in checkpoint:
             del checkpoint["tune_checkpoint_path"]
@@ -330,7 +330,7 @@ class FunctionRunner(Trainable):
         checkpoint_path = TrainableUtil.create_from_pickle(obj, checkpoint_dir)
         self.restore(checkpoint_path)
 
-    def _stop(self):
+    def cleanup(self):
         # If everything stayed in synch properly, this should never happen.
         if not self._results_queue.empty():
             logger.warning(