code: def testStruct2(self):
      iter1 = iter(typecodes)
      iter2 = iter(typecodes)
      iter3 = iter(typecodes)
      iterN = itertools.product(iter1, iter2, iter3)
      iterA = iter([False, True])
      for tp, align in itertools.product(iterN, iterA):
          t1, t2, t3 = tp
          spec = f"{t1},{t2},{t3}"
          with self.subTest(spec=spec, align=align):
              self.check(spec, align)
  
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 6 for calling the TestUtilDTLib obj's underlying member method code with example usage: obj.testStruct2() without return types