code: def return_fv_by_seeds(fv, seeds=None, unique_cls=None):
      
      if seeds is not None:
          if unique_cls is not None:
              return select_from_fv_by_seeds(fv, seeds, unique_cls)
          else:
              raise AssertionError("Input unique_cls has to be not None if seeds is not None.")
      else:
          return fv
docs: Return features selected by seeds and unique_cls or selection from features and corresponding seed classes.
  
      :param fv: ndarray with lineariezed feature. It's shape is MxN, where M is number of image pixels and N is number
      of features
      :param seeds: ndarray with seeds. Does not to be linear.
      :param unique_cls: number of used seeds clases. Like [1, 2]
      :return: fv, sd - selection from feature vector and selection from seeds or just fv for whole image