def __new__(cls, *args, **keys):
    if (cls._instance is None):
        cls._instance = object.__new__(cls)
        cls.proto = tk.IntVar(value=DEF_PROTO)
        cls.ip = tk.StringVar()
        cls.port = tk.IntVar(value=DEF_DST_PROT)
    return cls._instance
def __new__(cls, *args, **keys):
    if (cls._instance is None):
        cls._instance = object.__new__(cls)
        cls.proto = tk.IntVar(value=DEF_PROTO)
        cls.ip = tk.StringVar()
        cls.port = tk.IntVar(value=DEF_DST_PROT)
    return cls._instance