Add the Gene objects for a variant

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)