def remove(self, idx: int) -> Option[u]:
try:
_ = self[idx]
del self[idx]
return some(_)
except IndexError:
return none
def rsplit_once(self, u: u) -> Option[(str, str)]:
opt_idx = self.rchar_index(u)
if opt_idx is none: return none
first, last = self.split_at(opt_idx.unwrap())
last.remove(0)
return some((str(first), str(last)))
def rchar_index(self, u: u) -> Option[int]:
try:
return some(len(self) - 1 - self[::-1].index(u))
except ValueError:
return none
def char_index(self, u: u) -> Option[int]:
try:
return some(self.index(u))
except ValueError:
return none
def pop(self) -> Option[u]:
try:
return some(super().pop())
except IndexError:
return none