code: def get_outgroup(self):
          
          if self.outgroup is not None:
              outgroup_taxonomy = ''
              for i in self.data.seq_records:
                  if self.outgroup == i.voucher_code:
                      outgroup_taxonomy = '{0}_{1}'.format(i.taxonomy['genus'],
                                                           i.taxonomy['species'])
                      break
              outgroup = '\noutgroup {0}_{1};'.format(self.outgroup,
                                                      outgroup_taxonomy)
          else:
              outgroup = ''
          return outgroup
docs: Generates the outgroup line from the voucher code specified by the
          user.