Installation of pygraphviz in MacOS 10.12 (Sierra)

First attempt to the installation failed because of missing graphviz:

(django_python_env) MBP:mysite jhartman$ pip3 install pygraphviz
Collecting pygraphviz
 Downloading pygraphviz-1.3.1.zip (123kB)
 100% |████████████████████████████████| 133kB 1.4MB/s
Building wheels for collected packages: pygraphviz
 Running setup.py bdist_wheel for pygraphviz ... error
 Complete output