def range_data_nomerge(main_data, added_data):
  """
  Take main data and then update clusters with the added data only if they do
  not already exist.  Return only the valid clusters (not full set)
  """
  ret_data = {}
  for cluster in added_data:
    if main_data.get(cluster) is None:
      ret_data[cluster] = added_data[cluster]

  return ret_data