Bases: abjad.core.interface._Interface
Completely empty namespace available for composer labelling.
abjad> t = Note(0, (1, 4))
abjad> t.history.previous_transform = 'foo'
abjad> t.history.previous_transform
'foo'
Abjad ignores HistoryInterface attributes and usage completely.
The HistoryInterface handles no LilyPond grob.