New in version 2.0.
Yield all pairs between sequences l and m:
abjad> from abjad.tools import sequencetools
abjad> for pair in sequencetools.yield_all_pairs_between_sequences([1, 2, 3], [4, 5]):
... pair
...
(1, 4)
(1, 5)
(2, 4)
(2, 5)
(3, 4)
(3, 5)
Return pair generator.