def shape(self) -> Optional[Tuple[Tuple]]:
        """Get the shape of multi-level pixel data.

        Returns:
            Optional[tuple]: A tuple of data shape at each level, or ``None``
            if the data has not been assigned.
        """
        if self.nlevel is None:
            return None

        return tuple(level.shape for level in self.levels())
Get the shape of multi-level pixel data.

        Returns:
            Optional[tuple]: A tuple of data shape at each level, or ``None``
            if the data has not been assigned.
        
mmpose/mmpose/structures/multilevel_pixel_data.py