code: def zkronv(ttA, ttB):
      
      Al = _vector.vector.to_list(ttA)
      Bl = _vector.vector.to_list(ttB)
      Hl = [_np.kron(B, A) for (A, B) in zip(Al, Bl)]
      return _vector.vector.from_list(Hl)
docs: Do kronecker product between vectors ttA and ttB.
      Look about kronecker at: https://en.wikipedia.org/wiki/Kronecker_product
      For details about operation refer: https://arxiv.org/abs/1802.02839
      :param ttA: first TT-vector;
      :param ttB: second TT-vector;
      :return: operation result in z-order