code: def forward_cpu(self, inputs):
      (q,) = inputs
      global _zeta_cpu
      if _zeta_cpu is None:
          try:
              from scipy import special
  
              _zeta_cpu = special.zeta
          except ImportError:
              raise ImportError(
                  "Scipy is not available. Forward computation"
                  " of zeta cannot be done."
              )
      self.retain_inputs((0,))
      return (utils.force_array(_zeta_cpu(self._x, q), dtype=q.dtype),)
  
file_path: chainer/chainer/functions/math/zeta.py
imports: from chainer.backends import cuda
  from chainer import function_node
  from chainer import utils
  from chainer.utils import type_check
label_desc: Use image node_id 4 for calling the Zeta obj's underlying member method code with example usage: obj.forward_cpu(inputs) and returns: utils