def clearstamps(self, n=None):
        if n is None:
            toDelete = self.stampItems[:]
        elif n >= 0:
            toDelete = self.stampItems[:n]
        else:
            toDelete = self.stampItems[n:]
        for item in toDelete:
            self._clearstamp(item)
        self._update()
Form should not advance if the hash is missing or bad
dataset/ETHPy150Open amrdraz/kodr/app/brython/www/src/Lib/site-packages/turtle.py/RawTurtle.clearstamps--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.3/django/contrib/formtools/tests/__init__.py/WizardTests.test_bad_hash