code: def test_dot():
      v1 = vector([1, 0])
      v2 = vector([0, 1])
      v3 = vector([-1, 0])
      assert dot(v1, v1) == 1
      assert dot(v1, v2) == 0
      assert dot(v1, v3) == -1
  
imports: from dlib import vector, vectors, vectorss, dot
  from pytest import raises
label_desc: Use image node_id 9 for calling a global function with example usage: test_dot() without return types