code: def test_vector_getitem():
      v = vector([1, 2, 3])
      assert v[0] == 1
      assert v[-1] == 3
      assert v[1] == v[-2]
  
imports: from dlib import vector, vectors, vectorss, dot
  from pytest import raises
label_desc: Use image node_id 5 for calling a global function with example usage: test_vector_getitem() without return types