[tune] tf2.0 testing and supporting callables (#5738)

python/ray/tune/experiment.py

@@ -6,11 +6,11 @@ import copy
 import logging
 import os
 import six
-import types
 
 from ray.tune.error import TuneError
 from ray.tune.registry import register_trainable
 from ray.tune.result import DEFAULT_RESULTS_DIR
+from ray.tune.sample import sample_from
 
 logger = logging.getLogger(__name__)
 
@@ -145,8 +145,7 @@ class Experiment(object):
     def _register_if_needed(cls, run_object):
         """Registers Trainable or Function at runtime.
 
-        Assumes already registered if run_object is a string. Does not
-        register lambdas because they could be part of variant generation.
+        Assumes already registered if run_object is a string.
         Also, does not inspect interface of given run_object.
 
         Arguments:
@@ -160,17 +159,16 @@ class Experiment(object):
 
         if isinstance(run_object, six.string_types):
             return run_object
-        elif isinstance(run_object, types.FunctionType):
-            if run_object.__name__ == "<lambda>":
-                logger.warning(
-                    "Not auto-registering lambdas - resolving as variant.")
-                return run_object
-            else:
+        elif isinstance(run_object, sample_from):
+            logger.warning("Not registering trainable. Resolving as variant.")
+            return run_object
+        elif isinstance(run_object, type) or callable(run_object):
+            name = "DEFAULT"
+            if hasattr(run_object, "__name__"):
                 name = run_object.__name__
-                register_trainable(name, run_object)
-                return name
-        elif isinstance(run_object, type):
-            name = run_object.__name__
+            else:
+                logger.warning(
+                    "No name detected on trainable. Using {}.".format(name))
             register_trainable(name, run_object)
             return name
         else: