a.foo(a=order(1),b=order(2),order(3),order(4),e=order(5),f=order(6))
a.foo(f=order(6),order(3),e=order(5),b=order(2),order(4),a=order(1))
a.foo(a=order(1),b=order(2),order(3),order(4),e=order(5),f=order(6))
a.foo(f=order(6),order(3),e=order(5),b=order(2),order(4),a=order(1))