你可以添加一个内部函数:

def public(self, args):
   def private(self.root, data):
       if (self.root != None):
          pass #do something with data

如果你真的需要那种程度的隐私的话。

Python允许带有双下划线前缀的私有类成员。这种技术在模块级别上不起作用，所以我认为这是Dive Into Python中的一个错误。

下面是一个私有类函数的例子:

class foo():
    def bar(self): pass
    def __bar(self): pass

f = foo()
f.bar()   # this call succeeds
f.__bar() # this call fails

对于方法:(我不确定这是否是你想要的)

print_thrice.py

def private(method):
    def methodist(string):
        if __name__ == "__main__":
            method(string)
    return methodist
    
@private
def private_print3(string):
    print(string * 3)

private_print3("Hello ") # output: Hello Hello Hello

other_file.py

from print_thrice import private_print3
private_print3("Hello From Another File? ") # no output

这可能不是一个完美的解决方案，因为您仍然可以“看到”和/或“调用”该方法。不管怎样，它不会执行。

可能会混淆类私有和模块私有。

模块私有以一个下划线开始 当使用import命令的from <module_name> import *形式时，不会复制这样的元素;但是，如果使用import <moudule_name>语法，则会导入它(参见Ben Wilhelm的回答) 只要从问题示例的a.__num中删除一个下划线，它就不会在使用from a import *语法导入a.py的模块中显示出来。

A class private starts with two underscores (aka dunder i.e. d-ouble under-score) Such a variable has its name "mangled" to include the classname etc. It can still be accessed outside of the class logic, through the mangled name. Although the name mangling can serve as a mild prevention device against unauthorized access, its main purpose is to prevent possible name collisions with class members of the ancestor classes. See Alex Martelli's funny but accurate reference to consenting adults as he describes the convention used in regards to these variables.

>>> class Foo(object):
...    __bar = 99
...    def PrintBar(self):
...        print(self.__bar)
...
>>> myFoo = Foo()
>>> myFoo.__bar  #direct attempt no go
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: 'Foo' object has no attribute '__bar'
>>> myFoo.PrintBar()  # the class itself of course can access it
99
>>> dir(Foo)    # yet can see it
['PrintBar', '_Foo__bar', '__class__', '__delattr__', '__dict__', '__doc__', '__
format__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__',
'__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__
', '__subclasshook__', '__weakref__']
>>> myFoo._Foo__bar  #and get to it by its mangled name !  (but I shouldn't!!!)
99
>>>

这是一个古老的问题，但是模块私有(一个下划线)和类私有(两个下划线)被破坏的变量现在都包含在标准文档中:

Python教程»类»私有变量

Python有三种模式via。当导入一个模块时，只有public模式是可访问的。因此private和protected模块不能从模块外部调用，即当它被导入时。