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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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