def _add_file_from_data(
        self,
        key: str,
        value: (t.IO[bytes] | tuple[t.IO[bytes], str] | tuple[t.IO[bytes], str, str]),
    ) -> None:
        """Called in the EnvironBuilder to add files from the data dict."""
        if isinstance(value, tuple):
            self.files.add_file(key, *value)
        else:
            self.files.add_file(key, value)
Called in the EnvironBuilder to add files from the data dict.
src/werkzeug/test.py