code: def testSync(self):
      win = self.WIN
      comm = self.COMM
      rank = comm.Get_rank()
      with win_lock(win, rank):
          win.Sync()
      comm.Barrier()
  
imports: from mpi4py import MPI
  import mpiunittest
  import contextlib
  import arrayimpl
  import sys
label_desc: Use image node_id 19 for calling the BaseTestRMA obj's underlying member method code with example usage: obj.testSync() without return types