formatting

ml-agents/mlagents/trainers/torch/model_serialization.py

         for shape in self.policy.behavior_spec.observation_shapes:
             if len(shape) == 1:
                 vec_obs_size += shape[0]
-        num_vis_obs = sum(1 for shape in self.policy.behavior_spec.observation_shapes if len(shape) == 3)
+        num_vis_obs = sum(
+            1
+            for shape in self.policy.behavior_spec.observation_shapes
+            if len(shape) == 3
+        )
         dummy_vec_obs = [torch.zeros(batch_dim + [vec_obs_size])]
         # create input shape of NCHW
         # (It's NHWC in self.policy.behavior_spec.observation_shapes)