New in version 1.1.
True when arg has the form of a pair of integers that initialize a positive rational:
abjad> from abjad.tools import durationtools
abjad> durationtools.is_duration_pair((5, 16))
True
Otherwise false:
abjad> durationtools.is_duration_pair((-5, 16))
False
Return boolean.
Changed in version 2.0: renamed durationtools.is_pair() to durationtools.is_duration_pair().