docker image build crashing

I'm using the build.sh script located in the repo at /tools/docker. Here is the error I'm getting:

  File "/usr/local/lib/python2.7/dist-packages/pkg_resources/__init__.py", line 70, in <module>

    import packaging.version

ImportError: No module named packaging.version

----------------------------------------
Cleaning up...
Command /usr/bin/python -c "import setuptools, tokenize;__file__='/tmp/pip_build_root/SQLAlchemy/setup.py';exec(compile(getattr(tokenize, 'open', open)(__file__).read().replace('\r\n', '\n'), __file__, 'exec'))" install --record /tmp/pip-KWnOld-record/install-record.txt --single-version-externally-managed --compile failed with error code 1 in /tmp/pip_build_root/SQLAlchemy
Storing debug log for failure in /root/.pip/pip.log

I can provide the full log if necessary.

Thanks,
Hernán