old_contents: from mpi4py import MPI
  
  comm = MPI.COMM_WORLD
  rank = comm.Get_rank()
  
  data = [0,0]
  
  if rank == 0:
      data = [7,4]
      comm.send(data, 1, tag=11)
  elif rank == 1:
      data = comm.recv(source=0, tag=11)
      print(data)
      
  
new_contents: from mpi4py import MPI
  
  rank = -1
  #we must initialize rank
  comm = MPI.COMM_WORLD
  rank = comm.Get_rank()
  
  data = [0,0]
  
  if rank == 0:
      data = [7,4]
      comm.send(data, 1, tag=11)
  elif rank == 1:
      data = comm.recv(source=0, tag=11)
      print(data)
      
  
subject: clean example