diff --git a/turtlebot3_bringup/launch/turtlebot3_state_publisher.launch.py b/turtlebot3_bringup/launch/turtlebot3_state_publisher.launch.py
index 188e410e..f84c6139 100644
--- a/turtlebot3_bringup/launch/turtlebot3_state_publisher.launch.py
+++ b/turtlebot3_bringup/launch/turtlebot3_state_publisher.launch.py
@@ -21,7 +21,8 @@
 from ament_index_python.packages import get_package_share_directory
 from launch import LaunchDescription
 from launch.actions import DeclareLaunchArgument
-from launch.substitutions import LaunchConfiguration, PythonExpression
+from launch.substitutions import LaunchConfiguration
+from launch.substitutions import PythonExpression
 from launch_ros.actions import Node
 
 
diff --git a/turtlebot3_cartographer/launch/cartographer.launch.py b/turtlebot3_cartographer/launch/cartographer.launch.py
index 579aea92..af19ab3c 100644
--- a/turtlebot3_cartographer/launch/cartographer.launch.py
+++ b/turtlebot3_cartographer/launch/cartographer.launch.py
@@ -22,7 +22,8 @@
 from launch.actions import IncludeLaunchDescription
 from launch.conditions import IfCondition
 from launch.launch_description_sources import PythonLaunchDescriptionSource
-from launch.substitutions import LaunchConfiguration, ThisLaunchFileDir
+from launch.substitutions import LaunchConfiguration
+from launch.substitutions import ThisLaunchFileDir 
 from launch_ros.actions import Node