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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 get_recipe_instance(self, badge):
 """ Returns the recipe instance for the given badge slug. If badge has not been registered, raises ``exceptions.BadgeNotFound``. """

        from .exceptions import BadgeNotFound
        if badge in self._registry:
            return self.recipes[badge]
        raise BadgeNotFound()