def METHOD_NAME(self):
    if self.data:
        cmd = ['echo', self.data['log']]
    else:
        repodir, refname = self.download_history()
        cmd = ['ostree', 'log', '--repo', repodir, refname]
    pager = os.environ.get('PAGER')
    if pager:
        stdout = subprocess.PIPE
    else:
        stdout = None
    p = subprocess.Popen(cmd, stdout=stdout)
    if pager:
        subprocess.check_call((pager), stdin=p.stdout)
    p.wait()