old_contents: x = torch.tensor([0, 1, 2], dtype=torch.float32, requires_grad=True)
  y = torch.tensor(2 * x.data.clone(), requires_grad=True)
  
  cosine = g(x, y)
  print("cosine: ", cosine)
  
  cosine.backward()
  print('x.grad:', x.grad)
  print('y.grad:', y.grad)
  
  # The gradient of the cosine similarity of colinear vectors is
  # null w.r.t. each of the two vector as the cosine function
  # is already at its global maximum with a value of 1.0.
new_contents: x = torch.tensor([0, 1, 2], dtype=torch.float32, requires_grad=True)
  y = 2 * x.clone().detach()
  y.requires_grad_()
  
  cosine = g(x, y)
  print("cosine: ", cosine)
  
  cosine.backward()
  print('x.grad:', x.grad)
  print('y.grad:', y.grad)
  
  # The gradient of the cosine similarity of colinear vectors is
  # null w.r.t. each of the two vector as the cosine function
  # is already at its global maximum with a value of 1.0.
subject: Fix warning in solution