Requirements installation fails with swig error

We are having trouble installing the requirements file once curl’d down on Mac OSX Sierra with Python 2.7 and 3.6.1*., forcing the install with Python3 as such:

sudo curl https://raw.githubusercontent.com/automl/auto-sklearn/master/requirements.txt | xargs -n 1 -L 1 pip3 install

Most Python dependencies install without issue (we had most already), then we fail on pyfrf with the following trace:

Building wheels for collected packages: pyrfr
  Running setup.py bdist_wheel for pyrfr ... error
  Complete output from command /usr/local/opt/python3/bin/python3.6 -u -c "import setuptools, tokenize;__file__='/private/var/folders/46/rh_gbvxn2q19xbn10grfz3r00000gn/T/pip-build-2cdxyroo/pyrfr/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" bdist_wheel -d /var/folders/46/rh_gbvxn2q19xbn10grfz3r00000gn/T/tmpz8iuzdtbpip-wheel- --python-tag cp36:
  running bdist_wheel
  running build
  running build_py
  creating build
  creating build/lib.macosx-10.12-x86_64-3.6
  creating build/lib.macosx-10.12-x86_64-3.6/pyrfr
  copying pyrfr/__init__.py -> build/lib.macosx-10.12-x86_64-3.6/pyrfr
  running build_ext
  building '_regression' extension
  swigging pyrfr/regression.i to pyrfr/regression_wrap.cpp
  swig -python -c++ -I${CMAKE_SOURCE_DIR}/include -I./include -o pyrfr/regression_wrap.cpp pyrfr/regression.i
  unable to execute 'swig': No such file or directory
  error: command 'swig' failed with exit status 1
  
  ----------------------------------------
  Failed building wheel for pyrfr
  Running setup.py clean for pyrfr
Failed to build pyrfr
Installing collected packages: pyrfr
  Running setup.py install for pyrfr ... error
    Complete output from command /usr/local/opt/python3/bin/python3.6 -u -c "import setuptools, tokenize;__file__='/private/var/folders/46/rh_gbvxn2q19xbn10grfz3r00000gn/T/pip-build-2cdxyroo/pyrfr/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record /var/folders/46/rh_gbvxn2q19xbn10grfz3r00000gn/T/pip-1zqi87gy-record/install-record.txt --single-version-externally-managed --compile:
    running install
    running build_ext
    building '_regression' extension
    swigging pyrfr/regression.i to pyrfr/regression_wrap.cpp
    swig -python -c++ -I${CMAKE_SOURCE_DIR}/include -I./include -o pyrfr/regression_wrap.cpp pyrfr/regression.i
    unable to execute 'swig': No such file or directory
    error: command 'swig' failed with exit status 1
    
    ----------------------------------------
Command "/usr/local/opt/python3/bin/python3.6 -u -c "import setuptools, tokenize;__file__='/private/var/folders/46/rh_gbvxn2q19xbn10grfz3r00000gn/T/pip-build-2cdxyroo/pyrfr/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record /var/folders/46/rh_gbvxn2q19xbn10grfz3r00000gn/T/pip-1zqi87gy-record/install-record.txt --single-version-externally-managed --compile" failed with error code 1 in /private/var/folders/46/rh_gbvxn2q19xbn10grfz3r00000gn/T/pip-build-2cdxyroo/pyrfr/

*Python3 was installed via Homebrew