def _serialize(self, value, attr, obj):
        try:
            data = utils.to_marshallable_type(obj)
            return self.src_str.format(**data)
        except (__HOLE__, IndexError) as error:
            self.fail('format')
dataset/ETHPy150Open marshmallow-code/marshmallow/marshmallow/fields.py/FormattedString._serialize