Task:

$ ansible-galaxy init myrole

Problem: 

ModuleNotFoundError: No module named 'yaml'

Solution:

$ pip3 list pyyaml

$ pip3 install pyyaml

Set environment variable PYTHONUSERBASE

$ export PYTHONUSERBASE=/Users/aniu/Library/Python/3.7

$ python3 -m site --user-site

/Users/aniu/Library/Python/3.7/lib/python/site-packages