code: def psd(self, segment_duration, **kwds):
          
          from pycbc.psd import welch
          seg_len = int(segment_duration * self.sample_rate)
          seg_stride = int(seg_len / 2)
          return welch(self, seg_len=seg_len,
                             seg_stride=seg_stride,
                             **kwds)
docs: Calculate the power spectral density of this time series.
  
          Use the `pycbc.psd.welch` method to estimate the psd of this time segment.
          For more complete options, please see that function.
  
          Parameters
          ----------
          segment_duration: float
              Duration in seconds to use for each sample of the spectrum.
          kwds : keywords
              Additional keyword arguments are passed on to the `pycbc.psd.welch` method.
  
          Returns
          -------
          psd : FrequencySeries
              Frequency series containing the estimated PSD.