code: def _expandDH(self, sampling, lmax, lmax_calc):
          
          if self.normalization == '4pi':
              norm = 1
          elif self.normalization == 'schmidt':
              norm = 2
          elif self.normalization == 'unnorm':
              norm = 3
          elif self.normalization == 'ortho':
              norm = 4
          else:
              raise ValueError(
                  "Normalization must be '4pi', 'ortho', 'schmidt', or " +
                  "'unnorm'. Input value was {:s}"
                  .format(repr(self.normalization)))
  
          data = _shtools.MakeGridDHC(self.coeffs, sampling=sampling,
                                      norm=norm, csphase=self.csphase, lmax=lmax,
                                      lmax_calc=lmax_calc)
          gridout = SHGrid.from_array(data, grid='DH', copy=False)
          return gridout
docs: Evaluate the coefficients on a Driscoll and Healy (1994) grid.