avoid errors in some ide docs system

there are some error linked to repeated import of this module in spyder, an env with the same id cannot be registered again

examples/pybullet/gym/pybullet_envs/__init__.py

@@ -1,4 +1,10 @@
-from gym.envs.registration import registry, register, make, spec
+import gym
+from gym.envs.registration import registry, make, spec
+def register(id,*args,**kvargs):
+	if id in  registry.env_specs:
+		return
+	else:
+		return gym.envs.registration.register(id,*args,**kvargs)
 
 # ------------bullet-------------