code: def notch(self, frequency, type='iir', filtfilt=True, **kwargs):
          
          zpk = filter_design.notch(frequency, self.sample_rate.value,
                                    type=type, **kwargs)
          return self.filter(*zpk, filtfilt=filtfilt)
docs: Notch out a frequency in this `TimeSeries`.
  
          Parameters
          ----------
          frequency : `float`, `~astropy.units.Quantity`
              frequency (default in Hertz) at which to apply the notch
  
          type : `str`, optional
              type of filter to apply, currently only 'iir' is supported
  
          **kwargs
              other keyword arguments to pass to `scipy.signal.iirdesign`
  
          Returns
          -------
          notched : `TimeSeries`
             a notch-filtered copy of the input `TimeSeries`
  
          See Also
          --------
          TimeSeries.filter
             for details on the filtering method
          scipy.signal.iirdesign
              for details on the IIR filter design method