diff --git a/docs/source/modules/block_builder.rst b/docs/source/modules/block_builder.rst
index 55431e3a..cc3add9f 100644
--- a/docs/source/modules/block_builder.rst
+++ b/docs/source/modules/block_builder.rst
@@ -5,14 +5,14 @@ Block builder
 Block blueprints
 ============
 
-.. automodule:: rostok.block_builder_api.block_blueprint
+.. automodule:: rostok.block_builder_api.block_blueprints
     :members:
     :undoc-members:
 
 Block parameters
 =======
 
-.. automodule:: rostok.block_builder_api.block_parameter
+.. automodule:: rostok.block_builder_api.block_parameters
     :members:
     :undoc-members:
 
diff --git a/docs/source/modules/graph_generators.rst b/docs/source/modules/graph_generators.rst
index 0bd53870..8c13b32a 100644
--- a/docs/source/modules/graph_generators.rst
+++ b/docs/source/modules/graph_generators.rst
@@ -5,7 +5,7 @@ Graph generation
 Design environment
 ==================
 
-.. automodule:: rostok.graph_generators.environment.design_environment
+.. automodule:: rostok.graph_generators.environments.design_environment
     :members:
     :undoc-members:
 
diff --git a/rostok/simulation_chrono/simulation_scenario.py b/rostok/simulation_chrono/simulation_scenario.py
index 0435d41b..aacd8324 100644
--- a/rostok/simulation_chrono/simulation_scenario.py
+++ b/rostok/simulation_chrono/simulation_scenario.py
@@ -1,6 +1,6 @@
 from copy import deepcopy
 import json
-from typing import List
+from typing import List, Optional
 
 import pychrono as chrono