def dict_to_env(d, pathsep=os.pathsep):
    '''
    Convert a python dict to a dict containing valid environment variable
    values.

    :param d: Dict to convert to an env dict
    :param pathsep: Path separator used to join lists(default os.pathsep)
    '''

    out_env = {}

    for k, v in d.iteritems():
        if isinstance(v, list):
            out_env[k] = pathsep.join(v)
        elif isinstance(v, string_types):
            out_env[k] = v
        else:
            raise TypeError('{} not a valid env var type'.format(type(v)))

    return out_env
Convert a python dict to a dict containing valid environment variable
    values.

    :param d: Dict to convert to an env dict
    :param pathsep: Path separator used to join lists(default os.pathsep)