New in version 2.0.
Yield groups of rests in sequence:
abjad> staff = Staff("c'8 d'8 r8 r8 <e' g'>8 <f' a'>8 g'8 a'8 r8 r8 <b' d''>8 <c'' e''>8")
abjad> f(staff)
\new Staff {
c'8
d'8
r8
r8
<e' g'>8
<f' a'>8
g'8
a'8
r8
r8
<b' d''>8
<c'' e''>8
}
abjad> for rest in resttools.yield_groups_of_rests_in_sequence(staff):
... rest
...
(Rest('r8'), Rest('r8'))
(Rest('r8'), Rest('r8'))
Return generator.