New in version 2.0.
Next integer partition following integer_partition in descending lex order:
abjad> from abjad.tools import mathtools
abjad> mathtools.next_integer_partition((8, 3))
(8, 2, 1)
abjad> mathtools.next_integer_partition((8, 2, 1))
(8, 1, 1, 1)
abjad> mathtools.next_integer_partition((8, 1, 1, 1))
(7, 4)
Input integer_partition must be sequence of positive integers.
Return integer partition as tuple of positive integers.