def get_ancestors(self):
        def _get_ancestors(node, ancestors):
            ancestors.extend(node.parents)
            for p in node.parents:
                _get_ancestors(p, ancestors)
        ancestors = []
        _get_ancestors(self, ancestors)
        return ancestors
clean up once
dataset/ETHPy150Open VisTrails/VisTrails/contrib/titan/class_tree.py/TreeNode.get_ancestors--crossover with--dataset/ETHPy150Open eoyilmaz/anima/tests/env/test_environment_variables.py/EnvironmentVariableSetupTestCase.tearDownClass