code: def test_mpi_weighted_mean():
      comm = MPI.COMM_WORLD
      with logger.scoped_configure(comm=comm):
          if comm.rank == 0:
              name2valcount = {"a": (10, 2), "b": (20, 3)}
          elif comm.rank == 1:
              name2valcount = {"a": (19, 1), "c": (42, 3)}
          else:
              raise NotImplementedError
          d = mpi_util.mpi_weighted_mean(comm, name2valcount)
          correctval = {"a": (10 * 2 + 19) / 3.0, "b": 20, "c": 42}
          if comm.rank == 0:
              assert d == correctval, "{} != {}".format(d, correctval)
  
          for name, (val, count) in name2valcount.items():
              for _ in range(count):
                  logger.logkv_mean(name, val)
          d2 = logger.dumpkvs()
          if comm.rank == 0:
              assert d2 == correctval
  
imports: from baselines.common import mpi_util
  from baselines import logger
  from baselines.common.tests.test_with_mpi import with_mpi
label_desc: Use image node_id 1 for calling a global function with example usage: test_mpi_weighted_mean() without return types