gym env backward compatibility due to gym 0.9.6 breaking changes

examples/pybullet/gym/pybullet_envs/bullet/simpleHumanoidGymEnv.py

@@ -12,7 +12,7 @@ import time
 import pybullet as p
 from . import simpleHumanoid
 import random
-
+from pkg_resources import parse_version
 
 import pybullet_data
 
@@ -110,7 +110,8 @@ class SimpleHumanoidGymEnv(gym.Env):
     print(reward)
     return reward
 
-  render = _render
-  reset = _reset
-  seed = _seed
-  step = _step
+  if parse_version(gym.__version__)>=parse_version('0.9.6'):
+    render = _render
+    reset = _reset
+    seed = _seed
+    step = _step