I am learning ROS on tutorials page and i created a catkinws but for the 2nd time when i used catkinmake command i get this error. I got an error about catkin_make earlier but i found the solve. Now for the ** AttributeError: module 'enum' has no attribute 'IntFlag'** i did not find sample error on Net. Anyone knows what is the problem?

komodo@komodo-desktop:~/catkin_ws$ catkin_make
Base path: /home/komodo/catkin_ws
Source space: /home/komodo/catkin_ws/src
Build space: /home/komodo/catkin_ws/build
Devel space: /home/komodo/catkin_ws/devel
Install space: /home/komodo/catkin_ws/install
####
#### Running command: "make cmake_check_build_system" in "/home/komodo/catkin_ws/build"
####
-- Using CATKIN_DEVEL_PREFIX: /home/komodo/catkin_ws/devel
-- Using CMAKE_PREFIX_PATH: /opt/ros/melodic
-- This workspace overlays: /opt/ros/melodic
-- Found PythonInterp: /usr/bin/python3 (found suitable version "3.6.8", minimum required is "2") 
-- Using PYTHON_EXECUTABLE: /usr/bin/python3
-- Using Debian Python package layout
-- Using empy: /usr/bin/empy
-- Using CATKIN_ENABLE_TESTING: ON
-- Call enable_testing()
-- Using CATKIN_TEST_RESULTS_DIR: /home/komodo/catkin_ws/build/test_results
-- Found gmock sources under '/usr/src/googletest': gmock will be built
-- Found PythonInterp: /usr/bin/python3 (found version "3.6.8") 
-- Found gtest sources under '/usr/src/googletest': gtests will be built
-- Using Python nosetests: /usr/bin/nosetests-2.7
Traceback (most recent call last):
  File "/opt/ros/melodic/share/catkin/cmake/parse_package_xml.py", line 38, in <module>
    import argparse
  File "/usr/lib/python3.6/argparse.py", line 89, in <module>
    import re as _re
  File "/usr/lib/python3.6/re.py", line 142, in <module>
    class RegexFlag(enum.IntFlag):
AttributeError: module 'enum' has no attribute 'IntFlag'
Error in sys.excepthook:
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 53, in apport_excepthook
    if not enabled():
  File "/usr/lib/python3/dist-packages/apport_python_hook.py", line 24, in enabled
    import re
  File "/usr/lib/python3.6/re.py", line 142, in <module>
    class RegexFlag(enum.IntFlag):
AttributeError: module 'enum' has no attribute 'IntFlag'

Original exception was:
Traceback (most recent call last):
  File "/opt/ros/melodic/share/catkin/cmake/parse_package_xml.py", line 38, in <module>
    import argparse
  File "/usr/lib/python3.6/argparse.py", line 89, in <module>
    import re as _re
  File "/usr/lib/python3.6/re.py", line 142, in <module>
    class RegexFlag(enum.IntFlag):
AttributeError: module 'enum' has no attribute 'IntFlag'
CMake Error at /opt/ros/melodic/share/catkin/cmake/safe_execute_process.cmake:11 (message):
  execute_process(/usr/bin/python3
  "/opt/ros/melodic/share/catkin/cmake/parse_package_xml.py"
  "/opt/ros/melodic/share/catkin/cmake/../package.xml"
  "/home/komodo/catkin_ws/build/catkin/catkin_generated/version/package.cmake")
  returned error code 1
Call Stack (most recent call first):
  /opt/ros/melodic/share/catkin/cmake/catkin_package_xml.cmake:74 (safe_execute_process)
  /opt/ros/melodic/share/catkin/cmake/all.cmake:167 (_catkin_package_xml)
  /opt/ros/melodic/share/catkin/cmake/catkinConfig.cmake:20 (include)
  CMakeLists.txt:56 (find_package)


-- Configuring incomplete, errors occurred!
See also "/home/komodo/catkin_ws/build/CMakeFiles/CMakeOutput.log".
See also "/home/komodo/catkin_ws/build/CMakeFiles/CMakeError.log".
Makefile:320: recipe for target 'cmake_check_build_system' failed
make: *** [cmake_check_build_system] Error 1


Invoking "make cmake_check_build_system" failed