Python object attributes named after the object

Question

Given this class:

class vtp_datum(object):

    def __init__(self,**kwargs):

            for x in kwargs:

                    setattr(self,'__'+x,kwargs[x])

    def __eq__(self,other):
            return isinstance(other,vtp_datum) and (self.__ip_address == other.__ip_address and self.__mac_address == other.__mac_address)


    def __hash__(self):
           return hash( (self.__ip_address,self.__mac_address))

and this dictionary:

bleh={'ip_address': '1.2.3.4’, 'mac_address': '00:30:36:3B:30:39', 'pid': '1', 'pdesc': 'Dummy text', 'pname': 'Dummy P Name', 'description': 'Dummy Description'}

I'm not understanding why there would be attributes named _vtp_datum__<attribute> (as opposed to just __<attribute>) or why the hash function throws an error indicating attributes are missing.

>>> a=vtp_datum(**bleh)
>>> dir(a)

['__class__', '__delattr__', '__description', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__ip_address', '__le__', '__lt__', '__mac_address', '__module__', '__ne__', , '__new__', '__pdesc', '__pid', '__pname', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__']
>>> a.__hash__()

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

  File "ctest.py", line 24, in __hash__

    return hash( (self.__ip_address,self.__mac_address))

AttributeError: 'vtp_datum' object has no attribute '_vtp_datum__ip_address'

I tried it in a separate test module and the same thing happened (kinda). Maybe I haven't been paying attention but I never noticed class attributes that included the class name.

class blah:

        def __init__(self,name):

                self.__cheese = "craft"

                setattr(self,'_name',name)


        @property
        def cheese(self):

                return self.__cheese

        @property
        def name(self):
                return self._name

>>> a=blah('yep')
>>> dir(a)

['__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', '_blah__cheese', '_name', 'cheese', 'name']

I'd appreciate some help understanding what's going on here. Thanks