code: def test_postmap_inplace(self, xp):
      def impl(x, y):
          y += x
          res = xp.sum(x, self.axis)
          y += res
  
      return impl
  
imports: import unittest
  import numpy
  import cupy
  from cupy import testing
  from cupy_tests.core_tests.fusion_tests import fusion_utils
label_desc: Use image node_id 7 for calling the TestFusionReductionAndElementwise obj's underlying member method code with example usage: obj.test_postmap_inplace(xp) and returns: impl