code: def forward_xp(self, inputs, xp):
      (a,) = inputs
      axis = self.axis
      if self.is_module:
          b = xp.argmax(a, axis)
      else:
          b = a.argmax(axis)
      return (b,)
  
imports: import unittest
  import chainer
  import numpy
  import chainerx.testing
  from chainerx_tests import op_utils
label_desc: Use image node_id 3 for calling the TestArgmax obj's underlying member method code with example usage: obj.forward_xp(inputs, xp) and returns: b