roslaunch costar_objects gazebo_kinect_training.launch

RLException: Invalid <param> tag: Cannot load command parameter [robot_description]: no such command [['/opt/ros/noetic/share/xacro/xacro.py', '/home/xj/catkin_ws/src/costar_objects/urdf/kinect_floating.urdf.xacro']]. 

Param xml is <param name="robot_description" command="$(arg urdf_file)"/>
The traceback for the exception was written to the log file
