[minor][tune] Support Type Hinting for py3 (#6571)

* fullargspec for new pyversion

* fi

docker/tune_test/Dockerfile

@@ -6,7 +6,7 @@ FROM ray-project/base-deps
 # a test runner.
 RUN conda install -y numpy
 RUN pip install -U pip
-RUN pip install -U https://ray-wheels.s3-us-west-2.amazonaws.com/latest/ray-0.9.0.dev-cp36-cp36m-manylinux1_x86_64.whl
+RUN pip install -U https://ray-wheels.s3-us-west-2.amazonaws.com/latest/ray-0.9.0.dev0-cp36-cp36m-manylinux1_x86_64.whl
 RUN pip install -U boto3
 # We install this after the latest wheels -- this should not override the latest wheels.
 # Needed to run Tune example with a 'plot' call - which does not actually render a plot, but throws an error.

python/ray/tune/function_runner.py

@@ -7,6 +7,7 @@ import time
 import inspect
 import threading
 import traceback
+import sys
 from six.moves import queue
 
 from ray.tune import track
@@ -248,7 +249,10 @@ def wrap_function(train_func):
 
     use_track = False
     try:
-        func_args = inspect.getargspec(train_func).args
+        if sys.version_info >= (3, 3):
+            func_args = inspect.getfullargspec(train_func).args
+        else:
+            func_args = inspect.getargspec(train_func).args
         use_track = ("reporter" not in func_args and len(func_args) == 1)
         if use_track:
             logger.info("tune.track signature detected.")