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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def flags(self, index):
 """Return the flags for the given index This will call :meth:`TreeItem.flags` for valid ones. :param index: the index to query :type index: :class:`QtCore.QModelIndex` :returns: None :rtype: None :raises: None """

        if index.isValid():
            item = index.internalPointer()
            return item.flags(index)
        else:
            super(TreeModel, self).flags(index)