code: def testScatterv(self):
      size = self.COMM.Get_size()
      rank = self.COMM.Get_rank()
      for array, typecode in arrayimpl.loop():
          for root in range(size):
              check = arrayimpl.scalar(root)
              for count in range(size):
                  sbuf = array(root, typecode, size * size)
                  rbuf = array(-1, typecode, count)
                  counts = [count] * size
                  displs = list(range(0, size * size, size))
                  sendbuf = sbuf.as_mpi_v(counts, displs)
                  if rank != root:
                      sendbuf = None
                  self.COMM.Scatterv(sendbuf, rbuf.as_mpi(), root)
                  for vr in rbuf:
                      self.assertEqual(vr, check)
  
imports: from mpi4py import MPI
  import mpiunittest
  import arrayimpl
label_desc: Use image node_id 4 for calling the BaseTestCCOVec obj's underlying member method code with example usage: obj.testScatterv() without return types