def __str__(self):
        authors = ' and '.join(a.name for a in self.authors.all())
        return (self.name, authors) % '%s by %s' if authors else self.name
dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.5/tests/modeltests/fixtures/models.py/Book.__str__/swapped operands of `%`