(self, index)
return self._contents[index]
Retrieve the child tree one level down at the given ``index``.

        If the index is not in the instance that this tree corresponds
        to and is not known by this tree, whatever error would be raised
        by ``instance.__getitem__`` will be propagated (usually this is
        some subclass of `LookupError`.
Retrieve the child tree one level down at the given ``index``.
Retrieve the child tree one level down at the given index .
def __getitem__(self, index):
        """
        Retrieve the child tree one level down at the given ``index``.

        If the index is not in the instance that this tree corresponds
        to and is not known by this tree, whatever error would be raised
        by ``instance.__getitem__`` will be propagated (usually this is
        some subclass of `LookupError`.
        """

        if self._instance is not _unset and index not in self:
            self._instance[index]
        return self._contents[index]
def __getitem__ ( self , index ) : if self . _instance is not _unset and index not in self : self . _instance [ index ] return self . _contents [ index ]