code: def mask_by_linear_ind(self, linear_inds):
          
          inds = self.linear_to_ij(linear_inds)
          return self.mask_by_ind(inds)
docs: Create a new image by zeroing out data at locations not in the
          given indices.
  
          Parameters
          ----------
          linear_inds : :obj:`numpy.ndarray` of int
              A list of linear coordinates.
  
          Returns
          -------
          :obj:`Image`
              A new Image of the same type, with data not indexed by inds set
              to zero.