def swap_volume(self, old_connection_info, new_connection_info,
                    instance, mountpoint, resize_to):
        instance_name = instance.name
        if instance_name not in self._mounts:
            self._mounts[instance_name] = {}
        self._mounts[instance_name][mountpoint] = new_connection_info
Traverses the tree in depth-first top-down order,
dataset/ETHPy150Open BU-NU-CLOUD-SP16/Trusted-Platform-Module-nova/nova/virt/fake.py/FakeDriver.swap_volume--crossover with--dataset/ETHPy150Open mikhaildubov/AST-text-analysis/east/asts/ast.py/AnnotatedSuffixTree.Node.traverse_depth_first_pre_order