Fix int not iterable error on make_env

Author: asrvsn

.gitignore

@@ -1,3 +1,3 @@
 __pycache__/
 *.egg-info/
-
+*.pyc

multiagent/environment.py

@@ -65,7 +65,7 @@ def __init__(self, world, reset_callback=None, reward_callback=None,
  self.action_space.append(total_action_space[0])
  # observation space
  obs_dim = len(observation_callback(agent, self.world))
- self.observation_space.append(spaces.Box(low=-np.inf, high=+np.inf, shape=(obs_dim),))
+ self.observation_space.append(spaces.Box(low=-np.inf, high=+np.inf, shape=(obs_dim,)))
  agent.action.c = np.zeros(self.world.dim_c)
 
  # rendering