code: def testF90Integer(self):
      for r in (1, 2, 4):
          factory = MPI.Datatype.Create_f90_integer
          args = (r,)
          self.check(None, factory, *args)
  
imports: from mpi4py import MPI
  import mpiunittest
  import struct
label_desc: Use image node_id 15 for calling the BaseTestDatatypeCreateMixin obj's underlying member method code with example usage: obj.testF90Integer() without return types