code: def snr_series_to_xml(snr_series, document, sngl_inspiral_id):
      
      snr_lal = snr_series.lal()
      snr_lal.name = 'snr'
      snr_lal.sampleUnits = ''
      snr_xml = _build_series(snr_lal, (u'Time', u'Time,Real,Imaginary'), None,
                              'deltaT', 's')
      snr_node = document.childNodes[-1].appendChild(snr_xml)
      eid_param = ligolw_param.Param.build(u'event_id', u'ilwd:char',
                                           sngl_inspiral_id)
      snr_node.appendChild(eid_param)
docs: Save an SNR time series into an XML document, in a format compatible
      with BAYESTAR.