def child_column_for_obj(self, obj):
        """Given an object, return name of its child column, or None."""
        try:
            col = self.columns_by_model[obj.__class__]
            return self.child_columns[col.name].name
        except __HOLE__:
            return None
dataset/ETHPy150Open mozilla/moztrap/moztrap/view/lists/finder.py/Finder.child_column_for_obj