def swaplevel(self, i=-<NUM_LIT:2>, j=-<NUM_LIT:1>, copy=True):
new_index = self.index.swaplevel(i, j)<EOL>return self._constructor(self._values, index=new_index,<EOL>copy=copy).__finalize__(self)<EOL>
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.