An error

[Merida222]

hello!When I typed 'roslaunch cleaning_robot path_planning.launch‘，the error
‘Traceback (most recent call last):
File "/opt/ros/kinetic/share/xacro/xacro.py", line 61, in
xacro.main()
AttributeError: 'module' object has no attribute 'main'' was appeared.
How to deal with it?
Thank you so much!