code: def testAlignmentPair(self):
      for pairtype in mpipairtypes:
          alignment1 = MPI._typealign(pairtype)
          self.assertIn(alignment1, (2, 4, 8, 16))
          if np_dtype is not None:
              alignment2 = tonumpy(pairtype).alignment
              self.assertEqual(alignment1, alignment2)
  
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 23 for calling the TestUtilDTLib obj's underlying member method code with example usage: obj.testAlignmentPair() without return types