              ``True`` if the flag should be set to indicate that the cache is being reset because of
              a legacy face set/centering mismatch. ``False`` if the cache is being reset because it
              has detected a reset flag from the opposite cache.
          """
          if set_flag:
              logger.warning("You are using legacy extracted faces but have selected '%s' centering "
                             "which is incompatible. Switching centering to 'legacy'",
                             self._centering)
          self._config["centering"] = "legacy"
          self._centering = "legacy"
          self._cache = {key: dict(cached=False) for key in self._cache}
          self._cache_full = False
          self._size = None
          if set_flag:
              self._has_reset = True
  
      def _add_aligned_face(self, filename, alignments, image_size):
          """ Add a :class:`lib.align.AlignedFace` object to the cache.
  
          Parameters
          ----------
          filename: str
              The file path for the current image
 
</s> remove         set_flag: bool
            ``True`` if the flag should be set to indicate that the cache is being reset because of
            a legacy face set/centering mismatch. ``False`` if the cache is being reset because it
            has detected a reset flag from the opposite cache.
 </s> add         detected_face: list
            The list of :class:`~lib.align.DetectedFace` objects corresponding to the batch
        batch: :class:`numpy.ndarray`
            The preallocated array to apply masks to
        side: str
            '"a"' or '"b"' the side that is being processed </s> remove     def _reset_cache(self, set_flag):
        """ In the event that a legacy extracted face has been seen, and centering is not legacy
        the cache will need to be reset for legacy centering.
 </s> add         If masks are not being used then this function returns having done nothing </s> remove         Returns
        -------
        bool
            ``True`` if the cache has been reset because of a face centering change due to
            legacy alignments, otherwise ``False``. """
        retval = self._has_reset
        if retval:
            logger.debug("Resetting 'has_reset' flag")
            self._has_reset = False
        return retval
 </s> add         Raises
        ------
        :class:`FaceswapError`
            If the number of images loaded is smaller than the selected batch size
        """
        length = len(self._images)
        msg = ("Number of images is lower than batch-size (Note that too few images may lead to "
               f"bad training). # images: {length}, batch-size: {self._batch_size}")
        try:
            assert length >= self._batch_size, msg
        except AssertionError as err:
            msg += ("\nYou should increase the number of images in your training set or lower "
                    "your batch-size.")
            raise FaceswapError(msg) from err </s> remove logger = logging.getLogger(__name__)  # pylint: disable=invalid-name

_FACE_CACHES = dict()


def _get_cache(side, filenames, config):
    """ Obtain a :class:`_Cache` object for the given side. If the object does not pre-exist then
    create it.

    Parameters
    ----------
    side: str
        `"a"` or `"b"`. The side of the model to obtain the cache for
    filenames: list
        The filenames of all the images. This can either be the full path or the base name. If the
        full paths are passed in, they are stripped to base name for use as the cache key.
    config: dict
        The user selected training configuration options

    Returns
    -------
    :class:`_Cache`
        The face meta information cache for the requested side
    """
    if not _FACE_CACHES.get(side):
        logger.debug("Creating cache. Side: %s", side)
        _FACE_CACHES[side] = _Cache(filenames, config)
    return _FACE_CACHES[side]


def _check_reset(face_cache):
    """ Check whether a given cache needs to be reset because a face centering change has been
    detected in the other cache.

    Parameters
    ----------
    face_cache: :class:`_Cache`
        The cache object that is checking whether it should reset

    Returns
    -------
    bool
        ``True`` if the given object should reset the cache, otherwise ``False``
    """
    check_cache = next((cache for cache in _FACE_CACHES.values() if cache != face_cache), None)
    retval = check_cache if check_cache is None else check_cache.check_reset()
    return retval
 </s> add if sys.version_info < (3, 8):
    from typing_extensions import get_args, Literal
else:
    from typing import get_args, Literal </s> remove     def check_reset(self):
        """ Check whether this cache has been reset due to a face centering change, and reset the
        flag if it has.
 </s> add     # << INTERNAL METHODS >> #
    def _validate_samples(self) -> None:
        """ Ensures that the total number of images within :attr:`images` is greater or equal to
        the selected :attr:`batch_size`.
        if not self._use_mask:
            return

        masks = np.array([face.get_training_masks() for face in detected_faces])
        batch[..., 3:] = masks

        logger.trace("side: %s, masks: %s, batch: %s",  # type: ignore
                     self._side, masks.shape, batch.shape)

    def _process_batch(self, filenames: List[str]) -> BatchType:
        """ Prepares data for feeding through subclassed methods.

        If this is the first time a face has been loaded, then it's meta data is extracted from the
        png header and added to :attr:`_face_cache`
              ``True`` if the flag should be set to indicate that the cache is being reset because of
              a legacy face set/centering mismatch. ``False`` if the cache is being reset because it
              has detected a reset flag from the opposite cache.
          """
        if not self._use_mask:
            return

        masks = np.array([face.get_training_masks() for face in detected_faces])
        batch[..., 3:] = masks

        logger.trace("side: %s, masks: %s, batch: %s",  # type: ignore
                     self._side, masks.shape, batch.shape)

    def _process_batch(self, filenames: List[str]) -> BatchType:
        """ Prepares data for feeding through subclassed methods.

        If this is the first time a face has been loaded, then it's meta data is extracted from the
        png header and added to :attr:`_face_cache`
        if not self._use_mask:
            return

        masks = np.array([face.get_training_masks() for face in detected_faces])
        batch[..., 3:] = masks

        logger.trace("side: %s, masks: %s, batch: %s",  # type: ignore
                     self._side, masks.shape, batch.shape)

    def _process_batch(self, filenames: List[str]) -> BatchType:
        """ Prepares data for feeding through subclassed methods.

        If this is the first time a face has been loaded, then it's meta data is extracted from the
        png header and added to :attr:`_face_cache`
        if not self._use_mask:
            return

        masks = np.array([face.get_training_masks() for face in detected_faces])
        batch[..., 3:] = masks

        logger.trace("side: %s, masks: %s, batch: %s",  # type: ignore
                     self._side, masks.shape, batch.shape)

    def _process_batch(self, filenames: List[str]) -> BatchType:
        """ Prepares data for feeding through subclassed methods.

        If this is the first time a face has been loaded, then it's meta data is extracted from the
        png header and added to :attr:`_face_cache`
        if not self._use_mask:
            return

        masks = np.array([face.get_training_masks() for face in detected_faces])
        batch[..., 3:] = masks

        logger.trace("side: %s, masks: %s, batch: %s",  # type: ignore
                     self._side, masks.shape, batch.shape)

    def _process_batch(self, filenames: List[str]) -> BatchType:
        """ Prepares data for feeding through subclassed methods.

        If this is the first time a face has been loaded, then it's meta data is extracted from the
        png header and added to :attr:`_face_cache`
        if not self._use_mask:
            return

        masks = np.array([face.get_training_masks() for face in detected_faces])
        batch[..., 3:] = masks

        logger.trace("side: %s, masks: %s, batch: %s",  # type: ignore
                     self._side, masks.shape, batch.shape)

    def _process_batch(self, filenames: List[str]) -> BatchType:
        """ Prepares data for feeding through subclassed methods.

        If this is the first time a face has been loaded, then it's meta data is extracted from the
        png header and added to :attr:`_face_cache`
        if not self._use_mask:
            return

        masks = np.array([face.get_training_masks() for face in detected_faces])
        batch[..., 3:] = masks

        logger.trace("side: %s, masks: %s, batch: %s",  # type: ignore
                     self._side, masks.shape, batch.shape)

    def _process_batch(self, filenames: List[str]) -> BatchType:
        """ Prepares data for feeding through subclassed methods.

        If this is the first time a face has been loaded, then it's meta data is extracted from the
        png header and added to :attr:`_face_cache`
        if not self._use_mask:
            return

        masks = np.array([face.get_training_masks() for face in detected_faces])
        batch[..., 3:] = masks

        logger.trace("side: %s, masks: %s, batch: %s",  # type: ignore
                     self._side, masks.shape, batch.shape)

    def _process_batch(self, filenames: List[str]) -> BatchType:
        """ Prepares data for feeding through subclassed methods.

        If this is the first time a face has been loaded, then it's meta data is extracted from the
        png header and added to :attr:`_face_cache`
        if not self._use_mask:
            return

        masks = np.array([face.get_training_masks() for face in detected_faces])
        batch[..., 3:] = masks

        logger.trace("side: %s, masks: %s, batch: %s",  # type: ignore
                     self._side, masks.shape, batch.shape)

    def _process_batch(self, filenames: List[str]) -> BatchType:
        """ Prepares data for feeding through subclassed methods.

        If this is the first time a face has been loaded, then it's meta data is extracted from the
        png header and added to :attr:`_face_cache`
        if not self._use_mask:
            return

        masks = np.array([face.get_training_masks() for face in detected_faces])
        batch[..., 3:] = masks

        logger.trace("side: %s, masks: %s, batch: %s",  # type: ignore
                     self._side, masks.shape, batch.shape)

    def _process_batch(self, filenames: List[str]) -> BatchType:
        """ Prepares data for feeding through subclassed methods.

        If this is the first time a face has been loaded, then it's meta data is extracted from the
        png header and added to :attr:`_face_cache`
        if not self._use_mask:
            return

        masks = np.array([face.get_training_masks() for face in detected_faces])
        batch[..., 3:] = masks

        logger.trace("side: %s, masks: %s, batch: %s",  # type: ignore
                     self._side, masks.shape, batch.shape)

    def _process_batch(self, filenames: List[str]) -> BatchType:
        """ Prepares data for feeding through subclassed methods.

        If this is the first time a face has been loaded, then it's meta data is extracted from the
        png header and added to :attr:`_face_cache`
        if not self._use_mask:
            return

        masks = np.array([face.get_training_masks() for face in detected_faces])
        batch[..., 3:] = masks

        logger.trace("side: %s, masks: %s, batch: %s",  # type: ignore
                     self._side, masks.shape, batch.shape)

    def _process_batch(self, filenames: List[str]) -> BatchType:
        """ Prepares data for feeding through subclassed methods.

        If this is the first time a face has been loaded, then it's meta data is extracted from the
        png header and added to :attr:`_face_cache`
        if not self._use_mask:
            return

        masks = np.array([face.get_training_masks() for face in detected_faces])
        batch[..., 3:] = masks

        logger.trace("side: %s, masks: %s, batch: %s",  # type: ignore
                     self._side, masks.shape, batch.shape)

    def _process_batch(self, filenames: List[str]) -> BatchType:
        """ Prepares data for feeding through subclassed methods.

        If this is the first time a face has been loaded, then it's meta data is extracted from the
        png header and added to :attr:`_face_cache`
        if not self._use_mask:
            return

        masks = np.array([face.get_training_masks() for face in detected_faces])
        batch[..., 3:] = masks

        logger.trace("side: %s, masks: %s, batch: %s",  # type: ignore
                     self._side, masks.shape, batch.shape)

    def _process_batch(self, filenames: List[str]) -> BatchType:
        """ Prepares data for feeding through subclassed methods.

        If this is the first time a face has been loaded, then it's meta data is extracted from the
        png header and added to :attr:`_face_cache`
        if not self._use_mask:
            return

        masks = np.array([face.get_training_masks() for face in detected_faces])
        batch[..., 3:] = masks

        logger.trace("side: %s, masks: %s, batch: %s",  # type: ignore
                     self._side, masks.shape, batch.shape)

    def _process_batch(self, filenames: List[str]) -> BatchType:
        """ Prepares data for feeding through subclassed methods.

        If this is the first time a face has been loaded, then it's meta data is extracted from the
        png header and added to :attr:`_face_cache`
  
          Parameters
          ----------
          filename: str
              The file path for the current image
keep keep keep keep replace replace replace replace replace replace replace replace replace replace replace replace replace replace keep keep keep keep keep
 Data Augmentation update (#1263)

- lib.detected_face
    - Subclass Masks for Landmark based masks
    - Add training mask propery + methods to DetectedFace
  - lib.training_training
    - subclass TrainingDataGenerator for training and preview data
    - Split cache into own module
    - Reduce thread count to 1 to prevent image corruption + data re-use
    - Process on largest model input/output size rather than stored image size
    - Size and crop masks during caching stage
    - Implement ring buffer for data flow
    - Fix preview reload bug
  - augmentation
    - typing
    - switch color aug order
    - better initialization
    - Fix warp + landmark warp to correctly apply at different image scales
    - Slightly improved warp caching
    - Don't store whether image is_preview. Handle all data as training images implicitly
  - plugins.trainer: Typing and fixes to work with trainingdata refactor 
lib/training/generator.py