code: def biased_spectrum(self, power, k, convention='power', unit='per_l',
                          **kwargs):
          
          return self._biased_spectrum(power, k, convention=convention,
                                       unit=unit, **kwargs)
docs: Calculate the multitaper (cross-)spectrum expectation of a
          localized function.
  
          Usage
          -----
          outspectrum = x.biased_spectrum(spectrum, k, [unit, power, taper_wt,
                                                        save_cg, ldata])
  
          Returns
          -------
          outspectrum : ndarray, shape (ldata+lwin+1)
              The expectation of the windowed spectrum, where ldata is the
              spherical-harmonic bandwidth of the input spectrum, and lwin is the
              spherical-harmonic bandwidth of the localization windows.
  
          Parameters
          ----------
          spectrum : ndarray, shape (ldata+1)
              The global spectrum.
          k : int
              The number of best-concentrated localization windows to use in
              constructing the windowed spectrum.
          convention : str, optional, default = 'power'
              The type of input global and output biased spectra: 'power' for
              power spectra, and 'energy' for energy spectra.
          unit : str, optional, default = 'per_l'
              The units of the input global and output biased spectra. If
              'per_l', the spectra contain the total contribution for each
              spherical harmonic degree l. If 'per_lm', the spectra contain the
              average contribution for each coefficient at spherical harmonic
              degree l.
          taper_wt : ndarray, optional, default = None
              The weights used in calculating the multitaper spectral estimates
              and standard error.
          save_cg : int, optional, default = 0
              If 1, the Clebsch-Gordon coefficients will be precomputed and saved
              for future use. If 0, the Clebsch-Gordon coefficients will be
              recomputed for each call.
          ldata : int, optional, default = len(power)-1
              The maximum degree of the global unwindowed spectrum.