code: def testGetSize(self):
      for dtype in datatypes:
          size = dtype.Get_size()
          self.assertEqual(dtype.size, size)
  
imports: from mpi4py import MPI
  import mpiunittest
  import struct
label_desc: Use image node_id 3 for calling the TestDatatype obj's underlying member method code with example usage: obj.testGetSize() without return types