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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def csd(self, other, fftlength=None, overlap=None, window='hann', **kwargs):
 """Calculate the CSD `FrequencySeries` for two `TimeSeries` Parameters other : `TimeSeries` the second `TimeSeries` in this CSD calculation fftlength : `float` number of seconds in single FFT, defaults to a single FFT covering the full duration overlap : `float`, optional number of seconds of overlap between FFTs, defaults to the recommended overlap for the given window (if given), or 0 window : `str`, `numpy.ndarray`, optional window function to apply to timeseries prior to FFT, see :func:`scipy.signal.get_window` for details on acceptable formats Returns ------- csd : `~gwpy.frequencyseries.FrequencySeries` a data series containing the CSD. """

        return spectral.psd(
            (self, other),
            spectral.csd,
            fftlength=fftlength,
            overlap=overlap,
            window=window,
            **kwargs
        )