Python command gico checking out the latest version of git branch by name substring

gico.py

#!/usr/bin/env python
"""Checkout the latest version of git branch by name substring"""

from __future__ import print_function

import sys

from subprocess import check_output


def sanitize(output):
    normalize = lambda br: br.strip(' *')
    return [normalize(br) for br in  output.decode('utf-8').split() if normalize(br)]


def ensure_single(matches):
    if len(matches) > 1:
        print('Multiple matches:', ' '.join(matches))
        sys.exit(1)
    else:
        return matches[0].rsplit('/')[-1]


def main(name):
    check_output(['git', 'fetch', 'origin'])
    remote_branches = sanitize(check_output(['git', 'branch', '-r']))
    local_branches = sanitize(check_output(['git', 'branch']))

    by_name = lambda branch: name in branch
    remote_matches = filter(by_name, remote_branches)
    local_matches = filter(by_name, local_branches)

    if remote_matches:
        name = ensure_single(remote_matches)
        check_output(['git', 'checkout', name])
        check_output(['git', 'pull', '--ff-only'])
    elif local_matches:
        name = ensure_single(local_matches)
        check_output(['git', 'checkout', name])
    else:
        print('no matching branches found')
        sys.exit(1)


if __name__ == '__main__':
    main(sys.argv[1])