code: def test_extend() -> None:
      dim = 1
      multilist = VectorLinkedList(dimension=dim)
      another_multilist = VectorLinkedList(dimension=dim)
  
      new_node = VectorNode(dim)
      another_node = VectorNode(dim)
  
      multilist.append(new_node, 0)
      multilist.append(another_node, 0)
  
      another_multilist.extend([new_node, another_node], 0)
      assert another_multilist.chain_length(0) == 2
      assert (
          another_multilist.sentinel.next[0]
          is multilist.sentinel.next[0]
      )
      assert (
          another_multilist.sentinel.next[0].next[0]
          is multilist.sentinel.next[0].next[0]
      )
  
file_path: nevergrad/nevergrad/optimization/multiobjective/test_hypervolume.py
imports: import numpy
  from .hypervolume import VectorNode, VectorLinkedList, HypervolumeIndicator
label_desc: Use image node_id 5 for calling a global function with example usage: test_extend() without return types