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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 taper(self, side='leftright'):
 """Taper the ends of this `TimeSeries` smoothly to zero. Parameters side : `str`, optional the side of the `TimeSeries` to taper, must be one of `'left'`, `'right'`, or `'leftright'` Returns ------- out : `TimeSeries` a copy of `self` tapered at one or both ends Raises ------ ValueError if `side` is not one of `('left', 'right', 'leftright')` Examples -------- To see the effect of the Planck-taper window, we can taper a sinusoidal `TimeSeries` at both ends: We can plot it to see how the ends now vary smoothly from 0 to 1: Notes ----- The :meth:`TimeSeries.taper` automatically tapers from the second stationary point (local maximum or minimum) on the specified side of the input. However, the method will never taper more than half the full width of the `TimeSeries`, and will fail if there are no stationary points. See :func:`~gwpy.signal.window.planck` for the generic Planck taper window, and see :func:`scipy.signal.get_window` for other common window formats. """

        # check window properties
        if side not in ('left', 'right', 'leftright'):
            raise ValueError("side must be one of 'left', 'right', "
                             "or 'leftright'")
        out = self.copy()
        # identify the second stationary point away from each boundary,
        # else default to half the TimeSeries width
        nleft, nright = 0, 0
        mini, = signal.argrelmin(out.value)
        maxi, = signal.argrelmax(out.value)
        if 'left' in side:
            nleft = max(mini[0], maxi[0])
            nleft = min(nleft, self.size/2)
        if 'right' in side:
            nright = out.size - min(mini[-1], maxi[-1])
            nright = min(nright, self.size/2)
        out *= planck(out.size, nleft=nleft, nright=nright)
        return out