Python 2 compatibility. (#5887)

python/ray/tune/log_sync.py

@@ -41,7 +41,7 @@ def log_sync_template():
             ).format(ssh_key=quote(ssh_key))
 
 
-class NodeSyncMixin():
+class NodeSyncMixin(object):
     """Mixin for syncing files to/from a remote dir to a local dir."""
 
     def __init__(self):

python/ray/tune/schedulers/hyperband.py

@@ -294,7 +294,7 @@ class HyperBandScheduler(FIFOScheduler):
         trial_runner.trial_executor.unpause_trial(trial)
 
 
-class Bracket():
+class Bracket(object):
     """Logical object for tracking Hyperband bracket progress. Keeps track
     of proper parameters as designated by HyperBand.
 

python/ray/tune/tests/test_commands.py

@@ -20,7 +20,7 @@ from ray.tune import commands
 from ray.tune.result import CONFIG_PREFIX
 
 
-class Capturing():
+class Capturing(object):
     def __enter__(self):
         self._stdout = sys.stdout
         sys.stdout = self._stringio = StringIO()