Mojave install error on step: catkin config --install ...

[weixingsun]

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Workspace configuration appears valid.

[build] Found '237' packages in 0.0 seconds.
Warning: generated devel space setup files have been deleted.
Starting >>> catkin

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Errors << catkin:cmake /Users/sun/Desktop/OpenAI/ros-install-osx/melodic_desktop_full_ws/logs/catkin/build.cmake.005.log
/usr/local/Cellar/python@@2/2.7.15_1/Frameworks/Python.framework/Versions/2.7/Resources/Python.app/Contents/MacOS/Python: can't find 'main' module in '/Library/Python/2.7/site-packages/em'
CMake Error at /Users/sun/Desktop/OpenAI/ros-install-osx/melodic_desktop_full_ws/src/catkin/cmake/safe_execute_process.cmake:11 (message):

execute_process(/Users/sun/Desktop/OpenAI/ros-install-osx/melodic_desktop_full_ws/build/catkin/catkin_generated/env_cached.sh
"/usr/local/bin/python2" "/Library/Python/2.7/site-packages/em"
"--raw-errors" "-F"
"/Users/sun/Desktop/OpenAI/ros-install-osx/melodic_desktop_full_ws/build/catkin/catkin_generated/pkg.develspace.context.pc.py"
"-o"
"/Users/sun/Desktop/OpenAI/ros-install-osx/melodic_desktop_full_ws/devel/.private/catkin/lib/pkgconfig/catkin.pc"
"/Users/sun/Desktop/OpenAI/ros-install-osx/melodic_desktop_full_ws/src/catkin/cmake/em/pkg.pc.em")
returned error code 1
Call Stack (most recent call first):
cmake/em_expand.cmake:25 (safe_execute_process)
cmake/catkin_package.cmake:324 (em_expand)
cmake/catkin_package.cmake:102 (_catkin_package)
CMakeLists.txt:11 (catkin_package)

....................

I googled about this issue, all answers tell to install empy instead of em, but it was Ubuntu , not OSX
Please help