code: def to_array(self, normalization=None, csphase=None, lmax=None):
          
          if normalization is None:
              normalization = self.normalization
          if csphase is None:
              csphase = self.csphase
          if lmax is None:
              lmax = self.lmax
  
          coeffs = _convert(self.coeffs, normalization_in=self.normalization,
                            normalization_out=normalization,
                            csphase_in=self.csphase, csphase_out=csphase,
                            lmax=lmax)
  
          return coeffs
docs: Return spherical harmonic coefficients as a numpy array.
  
          Usage
          -----
          coeffs = x.to_array([normalization, csphase, lmax])
  
          Returns
          -------
          coeffs : ndarry, shape (2, lmax+1, lmax+1)
              numpy ndarray of the spherical harmonic coefficients.
  
          Parameters
          ----------
          normalization : str, optional, default = x.normalization
              Normalization of the output coefficients: '4pi', 'ortho',
              'schmidt', or 'unnorm' for geodesy 4pi normalized, orthonormalized,
              Schmidt semi-normalized, or unnormalized coefficients,
              respectively.
          csphase : int, optional, default = x.csphase
              Condon-Shortley phase convention: 1 to exclude the phase factor,
              or -1 to include it.
          lmax : int, optional, default = x.lmax
              Maximum spherical harmonic degree to output. If lmax is greater
              than x.lmax, the array will be zero padded.
  
          Description
          -----------
          This method will return an array of the spherical harmonic coefficients
          using a different normalization and Condon-Shortley phase convention,
          and a different maximum spherical harmonic degree. If the maximum
          degree is smaller than the maximum degree of the class instance, the
          coefficients will be truncated. Conversely, if this degree is larger
          than the maximum degree of the class instance, the output array will be
          zero padded.