-

ml-agents/mlagents/trainers/learn.py

 from mlagents.trainers.training_status import GlobalTrainingStatus
 from mlagents_envs.base_env import BaseEnv
 from mlagents.trainers.subprocess_env_manager import SubprocessEnvManager
+from mlagents.trainers.simple_env_manager import SimpleEnvManager
 from mlagents_envs.side_channel.side_channel import SideChannel
 from mlagents_envs.side_channel.engine_configuration_channel import EngineConfig
 from mlagents_envs.timers import (
             target_frame_rate=engine_settings.target_frame_rate,
             capture_frame_rate=engine_settings.capture_frame_rate,
         )
-        env_manager = SubprocessEnvManager(
-            env_factory, engine_config, env_settings.num_envs
-        )
+        # env_manager = SubprocessEnvManager(
+        #     env_factory, engine_config, env_settings.num_envs
+        # )
+
+
+        env_manager = SimpleEnvManager(env_factory(0, []), env_parameter_manager)
 
         trainer_factory = TrainerFactory(
             trainer_config=options.behaviors,