docs: def _add_genes(self, variant_obj):
          """Add the Gene objects for a variant"""
          genes = []
          ensembl_ids = []
          hgnc_symbols = []
          
          if variant_obj.transcripts:
              for transcript in variant_obj.transcripts:
                  if transcript.ensembl_id:
                      ensembl_ids.append(transcript.ensembl_id)
                  if transcript.hgnc_symbol:
                      hgnc_symbols.append(transcript.hgnc_symbol)
  
          else:
              hgnc_symbols = variant_obj.gene_symbols
          
          genes = get_gene_info(
                          ensembl_ids=ensembl_ids, 
                          hgnc_symbols=hgnc_symbols
                          )
              
          for gene in genes:
              variant_obj.add_gene(gene)