@classmethod
def from_other_image(cls, input_image, output_dir, output_subformat=None):
    """Convert the other disk image into an image of this type.

        Args:
          input_image (DiskRepresentation): Existing image representation.
          output_dir (str): Output directory to store the new image in.
          output_subformat (str): Any relevant subformat information.

        Raises:
          NotImplementedError: non-trivial to convert other types to ISO
        """
    raise NotImplementedError('Not a valid target for conversion')
