def METHOD_NAME(self, tree):
    assert True
    return None
    horse = tree.create_child(tree.root.idx, CHILD_HORSE_NAME, 
        external_id=CHILD_HORSE_EXTERNAL_ID)
    assert horse.name == CHILD_HORSE_NAME
    assert horse.external_id == CHILD_HORSE_EXTERNAL_ID
    assert tree.tree[horse.idx] == horse
    cow = tree.create_child(tree.root.idx, CHILD_COW_NAME, 
        external_id=CHILD_COW_EXTERNAL_ID)
    assert cow.name == CHILD_COW_NAME
    assert cow.external_id == CHILD_COW_EXTERNAL_ID
    assert tree.tree[cow.idx] == cow