diff --git a/examples/pybullet/gym/pybullet_envs/env_bases.py b/examples/pybullet/gym/pybullet_envs/env_bases.py
index c03f0e608..bfc2c2ccc 100644
--- a/examples/pybullet/gym/pybullet_envs/env_bases.py
+++ b/examples/pybullet/gym/pybullet_envs/env_bases.py
@@ -70,7 +70,7 @@ class MJCFBaseBulletEnv(gym.Env):
 		self.potential = self.robot.calc_potential()
 		return s
 
-	def _render(self, mode, close):
+	def _render(self, mode, close=False):
 		if (mode=="human"):
 			self.isRender = True
 		if mode != "rgb_array":