docs: def fade_in(self, segment, duration, fade_type="linear"):
          """Adds a fade in to a segment in the composition
  
          :param segment: Segment to fade in to
          :type segment: :py:class:`radiotool.composer.Segment`
          :param duration: Duration of fade-in (in seconds)
          :type duration: float
          :returns: The fade that has been added to the composition
          :rtype: :py:class:`Fade`
          """
          f = Fade(segment.track, segment.comp_location_in_seconds,
                   duration, 0.0, 1.0, fade_type=fade_type)
          self.add_dynamic(f)
          return f