New in version 2.0.
Change clef and staff_position_number to named chromatic pitch:
abjad> clef = contexttools.ClefMark('treble')
abjad> for n in range(-6, 6):
... pitch = pitchtools.clef_and_staff_position_number_to_named_chromatic_pitch(clef, n)
... print '%s\t%s\t%s' % (clef.clef_name, n, pitch)
treble -6 c'
treble -5 d'
treble -4 e'
treble -3 f'
treble -2 g'
treble -1 a'
treble 0 b'
treble 1 c''
treble 2 d''
treble 3 e''
treble 4 f''
treble 5 g''
Return named chromatic pitch.