code: def test_sum(self, xp, dtype1, dtype2):
      return lambda x: x.sum(axis=0, dtype=dtype2)
  
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 2 for calling the TestFusionReductionSpecifyDtype obj's underlying member method code with example usage: obj.test_sum(xp, dtype1, dtype2) and returns: function