code: def _parse_allele_data(self):
          
  
          # Get allele frequencies if they exist.
          pref_freq, frequencies = self._parse_frequencies()
  
          info_clnvar_single_tags = ['ALLELEID', 'CLNSIG', 'CLNHGVS']
          cln_data = {x.lower(): self.info[x] if x in self.info else None
                      for x in info_clnvar_single_tags}
          cln_data.update(
              {'clndisdb': [x.split(',') for x in
                            self.info['CLNDISDB'].split('|')]
               if 'CLNDISDB' in self.info else []})
          cln_data.update({'clndn': self.info['CLNDN'].split('|') if
                           'CLNDN' in self.info else []})
          cln_data.update({'clnvi': self.info['CLNVI'].split(',')
                          if 'CLNVI' in self.info else []})
  
          try:
              sequence = self.alt_alleles[0]
          except IndexError:
              sequence = self.ref_allele
  
          allele = ClinVarAllele(frequency=pref_freq, sequence=sequence,
                                 **cln_data)
  
          # A few ClinVar variants are only reported as a combination with
          # other variants, and no single-variant effect is proposed. Skip these.
          if not cln_data['clnsig']:
              return []
  
          return [allele]
docs: Parse alleles for ClinVar VCF, overrides parent method.