code: def get_unique_nonzeros(arr):
      
      rois = np.unique(arr)
      rois = rois[np.nonzero(rois)]
      rois.sort()
  
      return rois
docs: Return a sorted list of the non-zero unique values of arr.
  
      Parameters
      ----------
      arr: numpy.ndarray
          The data array
  
      Returns
      -------
      list of items of arr.