'Return a |Tiff| instance parsed from the Exif APP1 segment of
*segment_length* at *offset* in *stream*.'

@classmethod
def _tiff_from_exif_segment(cls, stream, offset, segment_length):

    stream.seek((offset + 8))
    segment_bytes = stream.read((segment_length - 8))
    substream = BytesIO(segment_bytes)
    return Tiff.from_stream(substream)
