added metadata and reward_range for each tasks

envs/dmc.py

@@ -3,6 +3,7 @@ import numpy as np
 
 
 class DeepMindControl:
+    metadata = {}
     def __init__(self, name, action_repeat=1, size=(64, 64), camera=None):
         domain, task = name.split("_", 1)
         if domain == "cup":  # Only domain with multiple words.
@@ -19,6 +20,7 @@ class DeepMindControl:
         if camera is None:
             camera = dict(quadruped=2).get(domain, 0)
         self._camera = camera
+        self.reward_range = [-np.inf, np.inf]
 
     @property
     def observation_space(self):