docs: def extended_fade_out(self, segment, duration):
          """Add a fade-out to a segment that extends the beginning of the
          segment.
  
          :param segment: Segment to fade out
          :type segment: :py:class:`radiotool.composer.Segment`
          :param duration: Duration of fade-out (in seconds)
          :returns: The fade that has been added to the composition
          :rtype: :py:class:`Fade`
          """
          dur = int(duration * segment.track.samplerate)
          if segment.start + segment.duration + dur <\
                  segment.track.duration:
              segment.duration += dur
          else:
              raise Exception(
                  "Cannot create fade-out that extends past the track's end")
          score_loc_in_seconds = segment.comp_location_in_seconds +\
              segment.duration_in_seconds - duration
          f = Fade(segment.track, score_loc_in_seconds, duration, 1.0, 0.0)
          self.add_dynamic(f)
          return f