Add hgnc symbols to the variant
        
            If there are transcripts use the symbols found here,
            otherwise use phizz to get the gene ids.

def _add_hgnc_symbols(self, variant_obj):
        """Add hgnc symbols to the variant
        
            If there are transcripts use the symbols found here,
            otherwise use phizz to get the gene ids.
        """
        hgnc_symbols = set()
        if variant_obj.transcripts:
            for transcript in variant_obj.transcripts:
                if transcript.hgnc_symbol:
                    hgnc_symbols.add(transcript.hgnc_symbol)
        else:
            chrom = variant_obj.CHROM
            start = variant_obj.start
            stop = variant_obj.stop
        
            hgnc_symbols = get_gene_symbols(chrom, start, stop)
        #Make unique ids
        variant_obj.gene_symbols = list(hgnc_symbols)