New in version 2.0.
Add double bar to end of score:
abjad> staff = Staff("c'4 d'4 e'4 f'4")
abjad> scoretools.add_double_bar_to_end_of_score(staff)
BarLine('|.')(f'4)
abjad> f(staff)
\new Staff {
c'4
d'4
e'4
f'4
\bar "|."
}
Return double bar.