Enable master branch protection on all github repositories you are an owner of.

github_protect_master.py

#!/usr/bin/env python                                                                                                                                        
from __future__ import print_function

REPO_URL = 'git+git://github.com/sigmavirus24/github3.py.git'
import os
import sys

try:
    from github3 import login
except ImportError:
    print('Please install github3.py: pip install {0}'.format(REPO_URL))
    sys.exit(1)


def prompt(msg):
    """Output message and return striped input."""
    sys.stdout.write('{0}: '.format(msg))
    sys.stdout.flush()
    return sys.stdin.readline().strip()


def get_session():
    """Return a github session from GITHUB_KEY, or user/pass authentication."""
    key = os.getenv('GITHUB_KEY')
    if key:
        github = login(token=key)
    else:
        from getpass import getpass
        username = prompt('GITHUB Username')
        password = getpass('Password for {0}: '.format(username))
        github = login(username, password,
                       two_factor_callback=lambda: prompt('Two factor token'))
    return github


def main():
    github = get_session()
    for repository in github.repositories('owner'):
        master = repository.branch('master')
        if master.protection['enabled']:
            print(' Protected: {0}'.format(repository))
        else:
            print('Protecting: {0}'.format(repository))
            master.protect()
    return 0


if __name__ == '__main__':
    sys.exit(main())