New in version 1.1.
True when expr is a sequence all elements in expr are unequal:
abjad> from abjad.tools import sequencetools
abjad> sequencetools.all_are_unequal([1, 2, 3, 4, 9])
True
True when expr is an empty sequence:
abjad> sequencetools.all_are_unequal([])
True
False otherwise:
abjad> sequencetools.all_are_unequal(17)
False
Return boolean.
Changed in version 2.0: renamed sequencetools.is_unique() to sequencetools.all_are_unequal().