in nox.py [0:0]
def cover(session):
"""Run the final coverage report.
This outputs the coverage report aggregating coverage from the unit
test runs (not system test runs), and then erases coverage data.
"""
session.interpreter = 'python3.6'
session.install('coverage', 'pytest-cov')
session.run('coverage', 'report', '--show-missing', '--fail-under=97')
session.run('coverage', 'erase')