def get_os():
    """
    Return the operating system of the host machine.

    :return:
        One of these values: "windows", "linux", and "others".
    """
    import sys
    os_name = sys.platform
    if os_name.startswith('win'):
        return 'windows'
    elif os_name == 'linux':
        return 'linux'
    else:
        return 'others'
