[tune][minor] gpu warning (#5948)

* gpu

* formaat

* defaults

* format_and_check

* better registration

* fix

* fix

* trial

* foramt

* tune

python/ray/tune/ray_trial_executor.py

@@ -93,7 +93,7 @@ class RayTrialExecutor(TrialExecutor):
                 memory=trial.resources.memory,
                 object_store_memory=trial.resources.object_store_memory,
                 resources=trial.resources.custom_resources)(
-                    trial._get_trainable_cls())
+                    trial.get_trainable_cls())
 
         trial.init_logger()
         # We checkpoint metadata here to try mitigating logdir duplication
@@ -622,6 +622,11 @@ class RayTrialExecutor(TrialExecutor):
                 trial.runner.export_model.remote(trial.export_formats))
         return {}
 
+    def has_gpus(self):
+        if self._resources_initialized:
+            self._update_avail_resources()
+            return self._avail_resources.gpu > 0
+
 
 def _to_gb(n_bytes):
     return round(n_bytes / (1024**3), 2)