主要代码正在运行，但其他代码未运行

Question

我正在学习 python 中的设计模式，主题是 singleton 对象，所以我将主要代码编写为PRO003并将其导入PRO004 。 这是PRO003代码：

class SingletonObject(object):
    class __SingletonObject:
        def __init__(self):
            self.name = None

        def __str__(self):
            return '{0!r} {1}'.format(self, self.name)

        def _write_log(self, level, msg):
            with open(self.name, 'a') as log_file:
                log_file.write('[{0}] -> {1}\n'.format(level, msg))

        def critical(self, msg):
            self._write_log('CRITICAL', msg)

        def error(self, msg):
            self._write_log('ERROR', msg)

        def warning(self, msg):
            self._write_log('WARNING', msg)

        def info(self, msg):
            self._write_log('INFO', msg)

        def debug(self, msg):
            self._write_log('DEBUG', msg)

    instance = None

    def __new__(cls, *args, **kwargs):
        if not SingletonObject.instance:
            SingletonObject.instance = SingletonObject.__SingletonObject
        return SingletonObject.instance

    def __getattr__(self, name):
        return getattr(self.instance, name)

    def __setattr__(self, name):
        return setattr(self.instance, name)

这是PRO004代码：

from PRO003 import SingletonObject

obj1 = SingletonObject()
obj1.name = 'logger.txt'
obj1.error('This Code Have An Error')
print('File Name: ', obj1.name, 'Object Location: ', obj1)

obj2 = SingletonObject()
obj2.name = 'logger.txt'
obj2.warning('Be Careful About This Bug')
print('File Name: ', obj2.name, 'Object Location: ', obj2)

但这是 Output：

Traceback (most recent call last):
  File "D:\PYTHON PROJECTS\LEARN\DesignPatterns\S01\PRO004.py", line 5, in <module>
    obj1.error('This Code Have An Error')
TypeError: error() missing 1 required positional argument: 'msg'
[Finished in 0.097s]

我认为这段代码想要self ，但self没有给出，它是由 class 并且不能输入这是我的想法，但我不知道了？ 这段代码有什么问题？

Answer 1

Class __SingletonObject未被实例化

SingletonObject.instance = SingletonObject.__SingletonObject

改成

SingletonObject.instance = SingletonObject.__SingletonObject()