+ def replace_start(self, new_start: int) -> 'TokenRange':
+ """ Return a new token range with the new start.
+ """
+ return TokenRange(new_start, self.end)
+
+
+ def replace_end(self, new_end: int) -> 'TokenRange':
+ """ Return a new token range with the new end.
+ """
+ return TokenRange(self.start, new_end)
+
+
+ def split(self, index: int) -> Tuple['TokenRange', 'TokenRange']:
+ """ Split the span into two spans at the given index.
+ The index must be within the span.
+ """
+ return self.replace_end(index), self.replace_start(index)
+