Return a generic |_Marker| instance for the marker at *offset* in
        *stream* having *marker_code*.

def from_stream(cls, stream, marker_code, offset):
        """
        Return a generic |_Marker| instance for the marker at *offset* in
        *stream* having *marker_code*.
        """
        if JPEG_MARKER_CODE.is_standalone(marker_code):
            segment_length = 0
        else:
            segment_length = stream.read_short(offset)
        return cls(marker_code, offset, segment_length)