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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 shift(self, periods, freq=None):
 """ Shift index by desired number of time frequency increments. This method is for shifting the values of datetime-like indexes by a specified time increment a given number of times. Parameters periods : int Number of periods (or increments) to shift by, can be positive or negative. .. versionchanged:: 0.24.0 freq : pandas.DateOffset, pandas.Timedelta or string, optional Frequency increment to shift by. If None, the index is shifted by its own `freq` attribute. Offset aliases are valid strings, e.g., 'D', 'W', 'M' etc. Returns ------- pandas.DatetimeIndex Shifted index. See Also -------- Index.shift : Shift values of Index. PeriodIndex.shift : Shift values of PeriodIndex. """

        result = self._data._time_shift(periods, freq=freq)
        return type(self)(result, name=self.name)