Keyword Arguments:
      out (Tensor, optional) -- the output tensor.
Example::
      >>> x = torch.tensor([2., 4.])
      >>> torch.special.zeta(x, 1)
      tensor([1.6449, 1.0823])
      >>> torch.special.zeta(x, torch.tensor([1., 2.]))
      tensor([1.6449, 0.0823])
      >>> torch.special.zeta(2, torch.tensor([1., 2.]))
      tensor([1.6449, 0.6449])