Method key_not_in_mapping

mypy/messages.py:1536–1537

(self, key: str, context: Context)

        )

    def key_not_in_mapping(self, key: str, context: Context) -> None:
        self.fail(f'Key "{key}" not found in mapping', context, code=codes.STRING_FORMATTING)

    def string_interpolation_mixing_key_and_non_keys(self, context: Context) -> None:
        self.fail(