Why does Python 2.7 namedtuple implement __dict__?

Question

Implementation namedtuplein Python 2.7 implements __dict__. I am confused that it does; why do we need to make special __dict__if properties are already defined?

C:\tmp> python
Python 2.7.12 |Anaconda 4.1.1 (64-bit)| (default, Jun 29 2016, 11:07:13) [MSC v.1500 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
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>>> import collections
>>> x = collections.namedtuple('foo','bar baz', verbose=True)
class foo(tuple):
    'foo(bar, baz)'

    __slots__ = ()

    _fields = ('bar', 'baz')

    def __new__(_cls, bar, baz):
        'Create new instance of foo(bar, baz)'
        return _tuple.__new__(_cls, (bar, baz))

    @classmethod
    def _make(cls, iterable, new=tuple.__new__, len=len):
        'Make a new foo object from a sequence or iterable'
        result = new(cls, iterable)
        if len(result) != 2:
            raise TypeError('Expected 2 arguments, got %d' % len(result))
        return result

    def __repr__(self):
        'Return a nicely formatted representation string'
        return 'foo(bar=%r, baz=%r)' % self

    def _asdict(self):
        'Return a new OrderedDict which maps field names to their values'
        return OrderedDict(zip(self._fields, self))

    def _replace(_self, **kwds):
        'Return a new foo object replacing specified fields with new values'
        result = _self._make(map(kwds.pop, ('bar', 'baz'), _self))
        if kwds:
            raise ValueError('Got unexpected field names: %r' % kwds.keys())
        return result

    def __getnewargs__(self):
        'Return self as a plain tuple.  Used by copy and pickle.'
        return tuple(self)

    __dict__ = _property(_asdict)

    def __getstate__(self):
        'Exclude the OrderedDict from pickling'
        pass

    bar = _property(_itemgetter(0), doc='Alias for field number 0')

    baz = _property(_itemgetter(1), doc='Alias for field number 1')

Answer 1

They just thought it would be convenient. It turns out that it was more of a hassle than it was , causing problems with etching and with subclasses, and it was conceptually confusing anyway. More recent versions of Python no longer have this.