code: def _taper2coeffs(self, itaper):
          
          taperm = self.orders[itaper]
          coeffs = _np.zeros((2, self.lwin + 1, self.lwin + 1))
          if taperm < 0:
              coeffs[1, :, abs(taperm)] = self.tapers[:, itaper]
          else:
              coeffs[0, :, abs(taperm)] = self.tapers[:, itaper]
  
          return coeffs
docs: Return the spherical harmonic coefficients of the unrotated taper i
          as an array, where i = 0 is the best concentrated.