  
      def _get_stored_mask(self,
                           detected_face: DetectedFace,
                           centering: Literal["legacy", "face", "head"],
                           sub_crop_offset: Optional[np.ndarray]) -> np.ndarray:
          """ get the requested stored mask from the detected face object.
  
          Parameters
          ----------
          detected_face: :class:`lib.align.DetectedFace`
 
</s> remove                   sub_crop_offset: Optional[np.ndarray]) -> np.ndarray:
 </s> add                   source_offset: np.ndarray,
                  target_offset: np.ndarray) -> np.ndarray: </s> remove             sub_crop_offset: Optional[np.ndarray],
 </s> add             source_offset: np.ndarray,
            target_offset: np.ndarray, </s> remove         sub_crop_offset: :class:`numpy.ndarray`, optional
            The (x, y) offset to crop the mask from the center point.
 </s> add         source_offset: :class:`numpy.ndarray`
            The (x, y) offset for the mask at its stored centering
        target_offset: :class:`numpy.ndarray`
            The (x, y) offset for the mask at the requested target centering </s> remove         sub_crop_offset: :class:`numpy.ndarray`
            The (x, y) offset to crop the mask from the center point. Set to `None` if the mask
            does not need to be offset for alternative centering
 </s> add         source_offset: :class:`numpy.ndarray`
            The (x, y) offset for the mask at its stored centering
        target_offset: :class:`numpy.ndarray`
            The (x, y) offset for the mask at the requested target centering </s> remove         offset: :class:`numpy.ndarray`
            The (x, y) offset from the center point to return the mask for
        centering: str
 </s> add         source_offset: :class:`numpy.ndarray`
            The (x, y) offset for the mask at its stored centering
        target_offset: :class:`numpy.ndarray`
            The (x, y) offset for the mask at the requested target centering
         centering: str
                         source_offset: np.ndarray,
                         target_offset: np.ndarray) -> np.ndarray:
  
      def _get_stored_mask(self,
                           detected_face: DetectedFace,
                           centering: Literal["legacy", "face", "head"],
                         source_offset: np.ndarray,
                         target_offset: np.ndarray) -> np.ndarray:
          """ get the requested stored mask from the detected face object.
  
          Parameters
          ----------
          detected_face: :class:`lib.align.DetectedFace`
keep keep keep keep replace keep keep keep keep keep
 lib.detected_face.Mask
  - Add source + target offset and coverage to set_sub_crop method 
plugins/convert/mask/mask_blend.py