def children(self):
        """~TermList: The direct children of the `Term`.
        """
        if self._children is None:
            topdowns = tuple(Relationship.topdown())
            self._children = TermList()
            self._children.extend(
                [ other
                    for rship,others in six.iteritems(self.relations)
                        for other in others
                            if rship in topdowns
                ]
            )
        return self._children
~TermList: The direct children of the `Term`.