Failure in bulding flask app

Downloading (46kB)
100% |████████████████████████████████| 51kB 11.8MB/s
Complete output from command python egg_info:
Traceback (most recent call last):
File “”, line 1, in
File “/home/circleci/repo/venv/lib/python3.6/site-packages/setuptools/”, line 5, in
import distutils.core
File “/usr/local/lib/python3.6/distutils/”, line 16, in
from distutils.dist import Distribution
File “/usr/local/lib/python3.6/distutils/”, line 9, in
import re
File “/usr/local/lib/python3.6/”, line 142, in
class RegexFlag(enum.IntFlag):
AttributeError: module ‘enum’ has no attribute ‘IntFlag’


Command “python egg_info” failed with error code 1 in /tmp/pip-build-klihxmfc/enum34/
You are using pip version 9.0.1, however version 18.1 is available.
You should consider upgrading via the ‘pip install --upgrade pip’ command.
Exited with code 1

The build is here - (I am not sure if this is public)