code: def test_duplicate_axis(self):
      with self.assertRaises(ValueError):
          functions.sum(self.x, axis=(0, 0))
  
file_path: chainer/tests/chainer_tests/functions_tests/math_tests/test_sum.py
imports: import unittest
  import numpy
  from chainer import functions
  from chainer import testing
label_desc: Use image node_id 4 for calling the TestSumError obj's underlying member method code with example usage: obj.test_duplicate_axis() without return types