def setdefault(self, key, defval=None):
        """
        >>> d = OrderedDict(((1, 3), (3, 2), (2, 1)))
        >>> d.setdefault(1)
        3
        >>> d.setdefault(4) is None
        True
        >>> d
        OrderedDict([(1, 3), (3, 2), (2, 1), (4, None)])
        >>> d.setdefault(5, 0)
        0
        >>> d
        OrderedDict([(1, 3), (3, 2), (2, 1), (4, None), (5, 0)])
        """
        if key in self:
            return self[key]
        else:
            self[key] = defval
            return defval
dataset/ETHPy150Open editorconfig/editorconfig-vim/plugin/editorconfig-core-py/editorconfig/odict.py/OrderedDict.setdefault/original