code: def interpolate_bilinear_lonlat(self, lon, lat, values):
          
          if len(values) != self.npix:
              raise ValueError('values must be an array of length {0} (got {1})'.format(self.npix, len(values)))
          return interpolate_bilinear_lonlat(lon, lat, values, order=self.order)
docs: Interpolate values at specific longitudes/latitudes using bilinear interpolation
  
          If a position does not have four neighbours, this currently returns NaN.
  
          Parameters
          ----------
          lon, lat : :class:`~astropy.units.Quantity`
              The longitude and latitude values as :class:`~astropy.units.Quantity` instances
              with angle units.
          values : `~numpy.ndarray`
              1-D array with the values in each HEALPix pixel. This must have a
              length of the form 12 * nside ** 2 (and nside is determined
              automatically from this).
  
          Returns
          -------
          result : `~numpy.ndarray`
              1-D array of interpolated values