code: def test_node_remove_children_in_batch():
      """Test removing children all at the same time"""
      parent = TreeNode("test")
      child1 = TreeNode("test1")
      child2 = TreeNode("test2")
  
      parent.add_children(child1, child2)
  
      assert parent.children[0] is child1
      assert parent.children[1] is child2
      assert child1.parent is parent
      assert child2.parent is parent
  
      parent.drop_children(child1, child2)
  
      assert len(parent.children) == 0
      assert child1.parent is None
      assert child2.parent is None
  
imports: from orion.core.utils.tree import DepthFirstTraversal, PreOrderTraversal, TreeNode, flattened
label_desc: Use image node_id 11 for calling a global function with example usage: test_node_remove_children_in_batch() without return types