#!/usr/bin/env python

import os

def get_workdir(default=None):
    # HOME must always be last but you must not rely on it as existing.
    for v in ['WORKSPACE', 'TRAVIS_BUILD_DIR', 'HOME']:
        if v in os.environ:
            return os.environ[v]
    if not default:
        return os.path.expanduser("~")
    else:
        return default

x = get_workdir()
print(x)