docs: def fill_borders(self, *args):
          """Extrapolate tiepoint lons and lats to fill in the border of the
          chunks.
          """
  
          to_run = []
          cases = {"y": self._fill_row_borders,
                   "x": self._fill_col_borders}
          for dim in args:
              try:
                  to_run.append(cases[dim])
              except KeyError:
                  raise NameError("Unrecognized dimension: " + str(dim))
  
          for fun in to_run:
              fun()