diff --git a/documentation/source/scenario_description.ipynb b/documentation/source/scenario_description.ipynb
index f694f17be..3a0170bb7 100644
--- a/documentation/source/scenario_description.ipynb
+++ b/documentation/source/scenario_description.ipynb
@@ -553,7 +553,7 @@
     "    \"tracks\": {\n",
     "        \"vehicle1\": {\n",
     "\n",
-    "            # The type string in metadrive.scenario.MetaDriveType\n",
+    "            # The type string in metadrive.type.MetaDriveType\n",
     "            \"type\": \"VEHICLE\",\n",
     "\n",
     "            # The state dict. All values must have T elements.\n",
@@ -587,7 +587,7 @@
     "    \"dynamic_map_states\": {\n",
     "        \"trafficlight1\": {\n",
     "\n",
-    "            # The type string in metadrive.scenario.MetaDriveType\n",
+    "            # The type string in metadrive.type.MetaDriveType\n",
     "            \"type\": \"TRAFFIC_LIGHT\",\n",
     "\n",
     "            # The state dict. All values must have T elements.\n",
diff --git a/metadrive/manager/base_manager.py b/metadrive/manager/base_manager.py
index 04fe3076f..47b83bad2 100644
--- a/metadrive/manager/base_manager.py
+++ b/metadrive/manager/base_manager.py
@@ -305,8 +305,8 @@ def before_step(self):
         return step_infos
 
     def after_step(self, *args, **kwargs):
-        step_infos = self.for_each_active_agents(lambda v: v.after_step())
-        step_infos = self.try_actuate_agent(step_infos, stage="after_step")
+        step_infos = self.try_actuate_agent({}, stage="after_step")
+        step_infos.update(self.for_each_active_agents(lambda v: v.after_step()))
         return step_infos
 
     def _translate(self, d):
diff --git a/metadrive/scenario/scenario_description.py b/metadrive/scenario/scenario_description.py
index 587490b9d..5eeae81a7 100644
--- a/metadrive/scenario/scenario_description.py
+++ b/metadrive/scenario/scenario_description.py
@@ -47,7 +47,7 @@
         "tracks": {
             "vehicle1": {
 
-                # The type string in metadrive.scenario.MetaDriveType
+                # The type string in metadrive.type.MetaDriveType
                 "type": "VEHICLE",
 
                 # The state dict. All values must have T elements.
@@ -81,7 +81,7 @@
         "dynamic_map_states": {
             "trafficlight1": {
 
-                # The type string in metadrive.scenario.MetaDriveType
+                # The type string in metadrive.type.MetaDriveType
                 "type": "TRAFFIC_LIGHT",
 
                 # The state dict. All values must have T elements.