code: def sanitize(self, example):
         "Return a copy of example, with non-input attributes replaced by None."
         return [attr_i if i in self.inputs else None
                 for i, attr_i in enumerate(example)f sanitize(self, example):
         "Return a copy of example, with non-input attributes replaced by None."
         return [attr_i if i in self.inputs else None
                 for i, attr_i in enumerate(example)]
docs: Return a copy of example, with non-input attributes replaced by None.