将python2.7升级至python3.4后，Python错误object（）不接受任何参数

Question

bashhostlist.py

from __future__ import print_function
import subprocess
import sys
import logging

class Singleton(object):
    """
    Creating a  single object that will work for all the plugin
    We create an object with an attrubute of the file path which is same for all the plugins
    So rather than creating new object for all the same object works so making singleton
    """
    _instance = None

    def __new__(class_, *args, **kwargs):
        if not isinstance(class_._instance, class_):
            class_._instance = object.__new__(class_, *args, **kwargs)
        return class_._instance


class InventoryMgmt(Singleton): 
    hostlist = {'hostcontent':None}
    def __init__(self, path):
        """ bash file path where environement are set """
        self._scriptpath = path

Singleton类用于Singleton模式 。

错误类型：

该错误发生在python version3.4中，但未在python2.7中发生

错误日志：

2017-11-03 03:09:39,187 - root - INFO - Plugin started
2017-11-03 03:09:39,187 - root - INFO - Trying to fetch from etc_shadow_plugin
2017-11-03 03:09:39,187 - root - ERROR - object() takes no parameters
Traceback (most recent call last):
  File "/home/sjoshi/python3.4/check-acess/plugins/plugin_etc_shadow/plugin_etc_shadow.py", line 91, in run
    listofhost=phelper.getallthehosts(hostnamewithoutdollar, envscriptpath)
  File "/home/sjoshi/python3.4/check-acess/lib/sshplugin/sshplugin.py", line 172, in getallthehosts
    myhosts=hostname.InventoryMgmt(envscriptpath)
  File "/home/sjoshi/python3.4/check-acess/lib/inventory/bashhostlist.py", line 16, in __new__
    class_._instance = object.__new__(class_, *args, **kwargs)

这就是我打电话给全班的方式

myhosts=hostname.InventoryMgmt(envscriptpath)

错误消息中也清楚显示了

疑问：

即使存在采用一个参数的init （）方法，为什么也会抛出该错误。 最重要的是，在python2.7上运行时错误不存在

我已经确认它不是制表符和间距问题，我看到许多答案对此问题表示怀疑

Answer 1

您应该删除那些多余的参数。 在python2.7中，如果将额外的参数传递给object.__new__ ，则会发出DeprecationWarning ，但是默认情况下此警告已被抑制 ，如果使用-Wdefault开关运行脚本，则会看到：

$ python2 -Wdefault singleton.py
singleton.py:13: DeprecationWarning: object() takes no parameters
  class_._instance = object.__new__(class_, *args, **kwargs)
<__main__.InventoryMgmt object at 0x106a2fd90> <__main__.InventoryMgmt object at 0x106a2fd90> True

从python3.3开始，此警告已转换为错误。