AttributeError: module 'enum' has no attribute 'IntFlag' - fastai install
When I try install fastai (pip install fastai) i get following error:

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


Full traceback:

 Installing build dependencies ... error
  ERROR: Complete output from command /usr/bin/python3 /usr/local/lib/python3.6/dist-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-b8vreosn/overlay --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- setuptools wheel 'numpy==1.13.3; python_version=='"'"'2.7'"'"' and platform_system!='"'"'AIX'"'"'' 'numpy==1.13.3; python_version=='"'"'3.5'"'"' and platform_system!='"'"'AIX'"'"'' 'numpy==1.13.3; python_version=='"'"'3.6'"'"' and platform_system!='"'"'AIX'"'"'' 'numpy==1.14.5; python_version&gt;='"'"'3.7'"'"' and platform_system!='"'"'AIX'"'"'' 'numpy==1.16.0; python_version=='"'"'2.7'"'"' and platform_system=='"'"'AIX'"'"'' 'numpy==1.16.0; python_version=='"'"'3.5'"'"' and platform_system=='"'"'AIX'"'"'' 'numpy==1.16.0; python_version=='"'"'3.6'"'"' and platform_system=='"'"'AIX'"'"'' 'numpy==1.16.0; python_version&gt;='"'"'3.7'"'"' and platform_system=='"'"'AIX'"'"'':
  ERROR: Traceback (most recent call last):
    File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
      "__main__", mod_spec)
    File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
      exec(code, run_globals)
    File "/usr/local/lib/python3.6/dist-packages/pip/__main__.py", line 16, in &lt;module&gt;
      from pip._internal import main as _main  # isort:skip # noqa
    File "/usr/local/lib/python3.6/dist-packages/pip/_internal/__init__.py", line 4, in &lt;module&gt;
      import locale
    File "/usr/lib/python3.6/locale.py", line 16, in &lt;module&gt;
      import re
    File "/usr/lib/python3.6/re.py", line 142, in &lt;module&gt;
      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 &lt;module&gt;
      class RegexFlag(enum.IntFlag):
  AttributeError: module 'enum' has no attribute 'IntFlag'

  Original exception was:
  Traceback (most recent call last):
    File "/usr/lib/python3.6/runpy.py", line 193, in _run_module_as_main
      "__main__", mod_spec)
    File "/usr/lib/python3.6/runpy.py", line 85, in _run_code
      exec(code, run_globals)
    File "/usr/local/lib/python3.6/dist-packages/pip/__main__.py", line 16, in &lt;module&gt;
      from pip._internal import main as _main  # isort:skip # noqa
    File "/usr/local/lib/python3.6/dist-packages/pip/_internal/__init__.py", line 4, in &lt;module&gt;
      import locale
    File "/usr/lib/python3.6/locale.py", line 16, in &lt;module&gt;
      import re
    File "/usr/lib/python3.6/re.py", line 142, in &lt;module&gt;
      class RegexFlag(enum.IntFlag):
  AttributeError: module 'enum' has no attribute 'IntFlag'
  ----------------------------------------
ERROR: Command "/usr/bin/python3 /usr/local/lib/python3.6/dist-packages/pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-b8vreosn/overlay --no-warn-script-location --no-binary :none: --only-binary :none: -i https://pypi.org/simple -- setuptools wheel 'numpy==1.13.3; python_version=='"'"'2.7'"'"' and platform_system!='"'"'AIX'"'"'' 'numpy==1.13.3; python_version=='"'"'3.5'"'"' and platform_system!='"'"'AIX'"'"'' 'numpy==1.13.3; python_version=='"'"'3.6'"'"' and platform_system!='"'"'AIX'"'"'' 'numpy==1.14.5; python_version&gt;='"'"'3.7'"'"' and platform_system!='"'"'AIX'"'"'' 'numpy==1.16.0; python_version=='"'"'2.7'"'"' and platform_system=='"'"'AIX'"'"'' 'numpy==1.16.0; python_version=='"'"'3.5'"'"' and platform_system=='"'"'AIX'"'"'' 'numpy==1.16.0; python_version=='"'"'3.6'"'"' and platform_system=='"'"'AIX'"'"'' 'numpy==1.16.0; python_version&gt;='"'"'3.7'"'"' and platform_system=='"'"'AIX'"'"''" failed with error code 1 in None


Enum34 cause issues in many packages.I tried to solve this by using:

pip freeze | grep enum34

and

pip uninstall -y enum34

also i tried unset PYTHONPATH and I still get the same error.

pip show enum34 &lt;-- this command give: WARNING: Package(s) not found: enum34

PROBLEM SOLVED:

as I wrote earlier Enum34 cause issues in many packages. 

If you have a similar problem, just use:

pip uninstall -y enum34

My problem was that in my case I should use:

sudo pip uninstall -y enum34
