AttributeError: module 'enum' has no attribute 'IntFlag'

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for python3 user, the tutorial suggest to run:

$ catkin_make -DPYTHON_EXECUTABLE=/usr/bin/python3

to build the workspace.

however, following error may come:

AttributeError: module 'enum' has no attribute 'IntFlag'

https://github.com/iterative/dvc/issu...

found one answer from github, it says this error is caused by enum34, which is not support in newer version python3. if you uninstall this module, the error will be solved. but to uninstall enum34, you need to uninstall the melodic ROS also.

can anyone contact the maintainer to help to solve this weird issue???