def render(self, part, context):
        try:
            return self.mailparts[part].nodelist.render(context)
        except KeyError:
            return None
Assert a.startswith(fragment), with repr messaging on failure.
dataset/ETHPy150Open f4nt/djtracker/djtracker/utils.py/MailTemplate.render--crossover with--dataset/ETHPy150Open RoseOu/flasky/venv/lib/python2.7/site-packages/sqlalchemy/testing/assertions.py/startswith_