New in version 2.0.
Analyze expr and return chord class based on incomplete pitches.
abjad> from abjad.tools import tonalitytools
abjad> tonalitytools.analyze_incomplete_chord(Chord([7, 11], (1, 4)))
GMajorTriadInRootPosition
abjad> tonalitytools.analyze_incomplete_chord(Chord(['fs', 'g', 'b'], (1, 4)))
GMajorSeventhInSecondInversion
Return chord class.