Return a list of startup dirs

def _get_dirs(user_dir, startup_dir):
    '''
    Return a list of startup dirs
    '''
    try:
        users = os.listdir(user_dir)
    except WindowsError:  # pylint: disable=E0602
        users = []

    full_dirs = []
    for user in users:
        full_dir = os.path.join(user_dir, user, startup_dir)
        if os.path.exists(full_dir):
            full_dirs.append(full_dir)
    return full_dirs