code: def testProcNull(self):
      comm = self.COMM
      #
      comm.Sendrecv(None, MPI.PROC_NULL, 0, None, MPI.PROC_NULL, 0)
      comm.Sendrecv_replace(None, MPI.PROC_NULL, 0, MPI.PROC_NULL, 0)
      #
      comm.Send(None, MPI.PROC_NULL)
      comm.Isend(None, MPI.PROC_NULL).Wait()
      #
      comm.Ssend(None, MPI.PROC_NULL)
      comm.Issend(None, MPI.PROC_NULL).Wait()
      #
      buf = MPI.Alloc_mem(MPI.BSEND_OVERHEAD)
      MPI.Attach_buffer(buf)
      comm.Bsend(None, MPI.PROC_NULL)
      comm.Ibsend(None, MPI.PROC_NULL).Wait()
      MPI.Detach_buffer()
      MPI.Free_mem(buf)
      #
      comm.Rsend(None, MPI.PROC_NULL)
      comm.Irsend(None, MPI.PROC_NULL).Wait()
      #
      comm.Recv(None, MPI.PROC_NULL)
      comm.Irecv(None, MPI.PROC_NULL).Wait()
  
imports: from mpi4py import MPI
  import mpiunittest
  import itertools
  import arrayimpl
label_desc: Use image node_id 6 for calling the BaseTestP2PBuf obj's underlying member method code with example usage: obj.testProcNull() without return types