code: def get_psms(self):
          
          self.header, isob_header = prep.get_full_and_isobaric_headers(
              self.oldheader, self.lookup, self.isobaric, self.precursor)
          self.psms = prep.generate_psms_quanted(self.lookup, self.fn,
                                                 isob_header, self.oldheader,
                                                 self.isobaric, self.precursor)
docs: Creates iterator to write to new tsv. Contains input tsv
          lines plus quant data for these.