code: def testFailures(self):
      endian = ">" if np_dtype("<i").isnative else "<"
      self.assertRaises(ValueError, fromnumpy, np_dtype(endian + "i"))
      self.assertRaises(ValueError, fromnumpy, np_dtype("O"))
      self.assertRaises(ValueError, fromnumpy, np_dtype("V"))
      self.assertRaises(ValueError, tonumpy, MPI.DATATYPE_NULL)
      mt = MPI.INT.Create_resized(0, 32)
      self.assertRaises(ValueError, tonumpy, mt)
      mt.Free()
      mt = MPI.INT.Create_subarray([2], [1], [0])
      self.assertRaises(ValueError, tonumpy, mt)
      mt.Free()
  
imports: from mpi4py import MPI
  from mpi4py.util.dtlib import from_numpy_dtype
  from mpi4py.util.dtlib import to_numpy_dtype
  import sys, os
  import itertools
label_desc: Use image node_id 26 for calling the TestUtilDTLib obj's underlying member method code with example usage: obj.testFailures() without return types