('a', 1, 'x'),
('a', 1, 'y'),
('a', 2, 'x'),
('a', 2, 'y'),...('b', 0, 'x'),
('b', 0, 'y'),
('b', 1, 'x'),
('b', 1, 'y'),...('b', 2, 'x'),
('b', 2, 'y'),
('c', 0, 'x'),
('c', 0, 'y'),...('c', 1, 'x'),
('c', 1, 'y'),
('c', 2, 'x'),
('c', 2, 'y')],....index
Out[28]:
MultiIndex([('a', 'x'),
('a', 'y'),
('b', 'x'),
(