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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 swaplevel(self, i=-2, j=-1, copy=True):
 """ Swap levels i and j in a MultiIndex. Parameters i, j : int, str (can be mixed) Level of index to be swapped. Can pass level name as string. Returns ------- Series Series with levels swapped in MultiIndex. .. versionchanged:: 0.18.1 The indexes ``i`` and ``j`` are now optional, and default to the two innermost levels of the index. """

        new_index = self.index.swaplevel(i, j)
        return self._constructor(self._values, index=new_index,
                                 copy=copy).__finalize__(self)