def snpeff(self):
        """
        Annotation with snpEff 
        """
        # calculate time thread took to finish
        # logging.info('Starting snpEff')
        tstart = datetime.now()

        se = snpeff.Snpeff(self.vcf_file)
        std = se.run()

        tend = datetime.now()
        execution_time = tend - tstart