message: In ModelCheckpoint callback, properly close the file handle before removing the file.
diff: @@ -951,7 +951,7 @@ class ModelCheckpoint(Callback):
  # call. This is because the SyncOnReadVariable needs to be synced across
  # all the workers in order to be read, and all workers need to initiate
  # that.
  - temp_file_name = tempfile.mkstemp()[1]
  + file_handle, temp_file_name = tempfile.mkstemp()
  extension = os.path.splitext(self.filepath)[1]
  filepath = temp_file_name + '.' + extension
  @@ -987,6 +987,7 @@ class ModelCheckpoint(Callback):
  # not checkpoint.
  if K.in_multi_worker_mode(
  ) and not dc_context.get_current_worker_context().should_checkpoint:
  + os.close(file_handle)
  os.remove(filepath)
  