Resolve inconsistent exception paradigm.

DeepMind · alimuldal · commit 82690d18d2e4 · 2018-10-10T20:25:39.000+01:00
PiperOrigin-RevId: 207724232
diff --git a/dm_control/rl/control.py b/dm_control/rl/control.py
@@ -340,7 +340,7 @@ def step_spec(self, physics):
       that describe the shapes, dtypes and elementwise lower and upper bounds
       for the array(s) returned by `self.step`.
     """
-    raise NotImplementedError
+    raise NotImplementedError()
 
   @abc.abstractmethod
   def get_observation(self, physics):
