docs: def timemap_stretch(y, sr, time_map, rbargs=None):
      '''Apply a timemap stretch to an audio time series.
  
      A timemap stretch allows non-linear time-stretching by mapping source to
      target sample frame numbers for fixed time points within the audio data.
  
      This uses the `time` and `timemap` form for rubberband.
  
      Parameters
      ----------
      y : np.ndarray [shape=(n,) or (n, c)]
          Audio time series, either single or multichannel
  
      sr : int > 0
          Sampling rate of `y`
  
      time_map : list
          Each element is a tuple `t` of length 2 which corresponds to the
          source sample position and target sample position.
  
          If `t[1] < t[0]` the track will be sped up in this area.
  
          `time_map[-1]` must correspond to the lengths of the source audio and
          target audio.
  
      rbargs
          Additional keyword parameters for rubberband
  
          See `rubberband -h` for details.
  
      Returns
      -------
      y_stretch : np.ndarray
          Time-stretched audio
  
      Raises
      ------
      ValueError
          if `time_map` is not monotonic
          if `time_map` is not non-negative
          if `time_map[-1][0]` is not the input audio length
      '''
  
      if rbargs is None:
          rbargs = dict()
  
      is_positive = all(time_map[i][0] >= 0 and time_map[i][1] >= 0
                        for i in range(len(time_map)))
      is_monotonic = all(time_map[i][0] <= time_map[i+1][0] and
                         time_map[i][1] <= time_map[i+1][1]
                         for i in range(len(time_map)-1))
      if not is_positive:
          raise ValueError('time_map should be non-negative')
  
      if not is_monotonic:
          raise ValueError('time_map is not monotonic')
  
      if time_map[-1][0] != len(y):
          raise ValueError('time_map[-1] should correspond to the last sample')
  
      time_stretch = time_map[-1][1] * 1.0 / time_map[-1][0]
      rbargs.setdefault('--time', time_stretch)
  
      stretch_file = tempfile.NamedTemporaryFile(mode='w', suffix='.txt',
                                                 delete=False)
      try:
          for t in time_map:
              stretch_file.write('{:0} {:1}\n'.format(t[0], t[1]))
          stretch_file.close()
  
          rbargs.setdefault('--timemap', stretch_file.name)
          y_stretch = __rubberband(y, sr, **rbargs)
      finally:
          # Remove temp file
          os.unlink(stretch_file.name)
  
      return y_stretch