def mm_on_cpu(x, w):
  """
  (helper function) Perform matrix multiplication on CPU.
  PLEASE DO NOT EDIT THIS FUNCTION CALL.

  Input:
  - x: Tensor of shape (A, B), on CPU
  - w: Tensor of shape (B, C), on CPU

  Returns:
  - y: Tensor of shape (A, C) as described above. It should not be in GPU.
  """
  y = x.mm(w)
  return y