code: def testMatchSize(self):
      typeclass = MPI.TYPECLASS_INTEGER
      for size in self.match_size_integer:
          datatype = MPI.Datatype.Match_size(typeclass, size)
          self.assertEqual(size, datatype.size)
      typeclass = MPI.TYPECLASS_REAL
      for size in self.match_size_real:
          datatype = MPI.Datatype.Match_size(typeclass, size)
          self.assertEqual(size, datatype.size)
      typeclass = MPI.TYPECLASS_COMPLEX
      for size in self.match_size_complex:
          datatype = MPI.Datatype.Match_size(typeclass, size)
          self.assertEqual(size, datatype.size)
  
imports: from mpi4py import MPI
  import mpiunittest
  import struct
label_desc: Use image node_id 5 for calling the TestDatatype obj's underlying member method code with example usage: obj.testMatchSize() without return types