def children(self):
        if self._children is None:
            return set()
        else:
            return self._children

    #TODO parent() and children() should be properties
Add an author to an article.
dataset/ETHPy150Open concurrence/concurrence/lib/concurrence/core.py/Tasklet.children--crossover with--dataset/ETHPy150Open rmcgibbo/figshare/figshare/figshare.py/Figshare.add_author