code: def testBasic(self):
      for spec in typecodes:
          with self.subTest(spec=spec):
              self.check(spec)
      for mpit in datatypes:
          with self.subTest(name=mpit.name):
              self.check(mpit)
  
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 2 for calling the TestUtilDTLib obj's underlying member method code with example usage: obj.testBasic() without return types