docs: def create_isobaric_quant_lookup(quantdb, specfn_consensus_els, channelmap):
      """Creates an sqlite lookup table of scannrs with quant data.
  
      spectra - an iterable of tupled (filename, spectra)
      consensus_els - a iterable with consensusElements"""
      # store quantchannels in lookup and generate a db_id vs channel map
      channels_store = ((name,) for name, c_id
                        in sorted(channelmap.items(), key=lambda x: x[1]))
      quantdb.store_channelmap(channels_store)
      channelmap_dbid = {channelmap[ch_name]: ch_id for ch_id, ch_name in
                         quantdb.get_channelmap()}
      quants = []
      mzmlmap = quantdb.get_mzmlfile_map()
      for specfn, consensus_el in specfn_consensus_els:
          rt = openmsreader.get_consxml_rt(consensus_el)
          rt = round(float(Decimal(rt) / 60), 12)
          qdata = get_quant_data(consensus_el)
          spectra_id = quantdb.get_spectra_id(mzmlmap[specfn],
                                              retention_time=rt)
          for channel_no in sorted(qdata.keys()):
              quants.append((spectra_id, channelmap_dbid[channel_no],
                             qdata[channel_no]))
              if len(quants) == DB_STORE_CHUNK:
                  quantdb.store_isobaric_quants(quants)
      quantdb.store_isobaric_quants(quants)
      quantdb.index_isobaric_quants()