content: from .registry import DATASETS
  from .video_dataset import VideoDataset
  
  
  @DATASETS.register_module()
  class ImageDataset(VideoDataset):
      """Image dataset for action recognition, used in the Project OmniSource.
  
      The dataset loads image list and apply specified transforms to return a
      dict containing the image tensors and other information. For the
      ImageDataset
  
      The ann_file is a text file with multiple lines, and each line indicates
      the image path and the image label, which are split with a whitespace.
      Example of a annotation file:
  
      .. code-block:: txt
  
          path/to/image1.jpg 1
          path/to/image2.jpg 1
          path/to/image3.jpg 2
          path/to/image4.jpg 2
          path/to/image5.jpg 3
          path/to/image6.jpg 3
  
      Example of a multi-class annotation file:
  
      .. code-block:: txt
  
          path/to/image1.jpg 1 3 5
          path/to/image2.jpg 1 2
          path/to/image3.jpg 2
          path/to/image4.jpg 2 4 6 8
          path/to/image5.jpg 3
          path/to/image6.jpg 3
  
      Args:
          ann_file (str): Path to the annotation file.
          pipeline (list[dict | callable]): A sequence of data transforms.
          **kwargs: Keyword arguments for ``BaseDataset``.
      """
  
      def __init__(self, ann_file, pipeline, **kwargs):
          super().__init__(ann_file, pipeline, start_index=None, **kwargs)
          # use `start_index=None` to indicate it is for `ImageDataset`
  