code: def master_then_spare(data):
      
      master = []
      spare = []
      for sdata in data:
          if sdata.spare:
              spare.append(sdata)
          else:
              master.append(sdata)
      rdata = []
      rdata.extend(master)
      rdata.extend(spare)
      return rdata
docs: Return the provided satellites list sorted as:
          - alive first,
          - then spare
          - then dead
          satellites.
  
      :param data: the SatelliteLink list
      :type data: list
      :return: sorted list
      :rtype: list