Names of levels in MultiIndex.
Examples
>>> mi = pd.MultiIndex.from_arrays( ... [[1, 2], [3, 4], [5, 6]], names=['x', 'y', 'z']) >>> mi MultiIndex([(1, 3, 5), (2, 4, 6)], names=['x', 'y', 'z']) >>> mi.names FrozenList(['x', 'y', 'z'])