New in version 2.0.
Transpose pitch_carrier by diatonic melodic_interval:
abjad> chord = Chord("<c' e' g'>4")
abjad> pitchtools.transpose_pitch_carrier_by_melodic_interval(chord, '+m2')
Chord("<df' f' af'>4")
Transpose pitch_carrier by chromatic melodic_interval:
abjad> chord = Chord("<c' e' g'>4")
abjad> pitchtools.transpose_pitch_carrier_by_melodic_interval(chord, 1)
Chord("<cs' f' af'>4")
Return non-pitch-carrying input unchaged:
abjad> rest = Rest('r4')
abjad> pitchtools.transpose_pitch_carrier_by_melodic_interval(rest, 1)
Rest('r4')
Return pitch_carrier.