diff --git a/stdlib/2and3/_bisect.pyi b/stdlib/2and3/_bisect.pyi
index 4237e0508..43ee44bba 100644
--- a/stdlib/2and3/_bisect.pyi
+++ b/stdlib/2and3/_bisect.pyi
@@ -1,9 +1,9 @@
 """Stub file for the '_bisect' module."""
 
-from typing import Sequence, MutableSequence, TypeVar
+from typing import Optional, Sequence, MutableSequence, TypeVar
 
 _T = TypeVar('_T')
-def bisect_left(a: Sequence[_T], x: _T, lo: int = ..., hi: int = ...) -> int: ...
-def bisect_right(a: Sequence[_T], x: _T, lo: int = ..., hi: int = ...) -> int: ...
-def insort_left(a: MutableSequence[_T], x: _T, lo: int = ..., hi: int = ...) -> None: ...
-def insort_right(a: MutableSequence[_T], x: _T, lo: int = ..., hi: int = ...) -> None: ...
+def bisect_left(a: Sequence[_T], x: _T, lo: int = ..., hi: Optional[int] = ...) -> int: ...
+def bisect_right(a: Sequence[_T], x: _T, lo: int = ..., hi: Optional[int] = ...) -> int: ...
+def insort_left(a: MutableSequence[_T], x: _T, lo: int = ..., hi: Optional[int] = ...) -> None: ...
+def insort_right(a: MutableSequence[_T], x: _T, lo: int = ..., hi: Optional[int] = ...) -> None: ...