Fix linting on master (#4077)

python/ray/rllib/agents/pg/pg.py

@@ -57,6 +57,6 @@ class PGAgent(Agent):
         self.optimizer.step()
         result = self.optimizer.collect_metrics(
             self.config["collect_metrics_timeout"])
-        result.update(
-            timesteps_this_iter=self.optimizer.num_steps_sampled - prev_steps)
+        result.update(timesteps_this_iter=self.optimizer.num_steps_sampled -
+                      prev_steps)
         return result

python/ray/rllib/agents/pg/torch_pg_policy_graph.py

@@ -22,7 +22,6 @@ class PGLoss(nn.Module):
     def forward(self, observations, actions, advantages):
         logits, _, values, _ = self.policy_model({"obs": observations}, [])
         log_probs = F.log_softmax(logits, dim=1)
-        probs = F.softmax(logits, dim=1)
         action_log_probs = log_probs.gather(1, actions.view(-1, 1))
         pi_err = -advantages.dot(action_log_probs.reshape(-1))
         return pi_err