Akuli and srittau: Remove Python 2 branches from Python 3 stubs (#5461)

* run script and do some manual changes (Akuli)

* do the whole thing manually (srittau)

* merge changes (Akuli)

Co-authored-by: Sebastian Rittau <srittau@rittau.biz>

stdlib/weakref.pyi

@@ -1,4 +1,3 @@
-import sys
 import types
 from _weakrefset import WeakSet as WeakSet
 from typing import (
@@ -29,9 +28,6 @@ from _weakref import (
     ref as ref,
 )
 
-if sys.version_info < (3, 0):
-    from exceptions import ReferenceError as ReferenceError
-
 _S = TypeVar("_S")
 _T = TypeVar("_T")
 _KT = TypeVar("_KT")
@@ -39,10 +35,9 @@ _VT = TypeVar("_VT")
 
 ProxyTypes: Tuple[Type[Any], ...]
 
-if sys.version_info >= (3, 4):
-    class WeakMethod(ref[types.MethodType]):
-        def __new__(cls, meth: types.MethodType, callback: Optional[Callable[[types.MethodType], Any]] = ...) -> WeakMethod: ...
-        def __call__(self) -> Optional[types.MethodType]: ...
+class WeakMethod(ref[types.MethodType]):
+    def __new__(cls, meth: types.MethodType, callback: Optional[Callable[[types.MethodType], Any]] = ...) -> WeakMethod: ...
+    def __call__(self) -> Optional[types.MethodType]: ...
 
 class WeakValueDictionary(MutableMapping[_KT, _VT]):
     @overload
@@ -53,24 +48,14 @@ class WeakValueDictionary(MutableMapping[_KT, _VT]):
     def __getitem__(self, k: _KT) -> _VT: ...
     def __setitem__(self, k: _KT, v: _VT) -> None: ...
     def __delitem__(self, v: _KT) -> None: ...
-    if sys.version_info < (3, 0):
-        def has_key(self, key: object) -> bool: ...
     def __contains__(self, o: object) -> bool: ...
     def __iter__(self) -> Iterator[_KT]: ...
     def __str__(self) -> str: ...
     def copy(self) -> WeakValueDictionary[_KT, _VT]: ...
-    if sys.version_info >= (3, 0):
-        # These are incompatible with Mapping
-        def keys(self) -> Iterator[_KT]: ...  # type: ignore
-        def values(self) -> Iterator[_VT]: ...  # type: ignore
-        def items(self) -> Iterator[Tuple[_KT, _VT]]: ...  # type: ignore
-    else:
-        def keys(self) -> List[_KT]: ...
-        def values(self) -> List[_VT]: ...
-        def items(self) -> List[Tuple[_KT, _VT]]: ...
-        def iterkeys(self) -> Iterator[_KT]: ...
-        def itervalues(self) -> Iterator[_VT]: ...
-        def iteritems(self) -> Iterator[Tuple[_KT, _VT]]: ...
+    # These are incompatible with Mapping
+    def keys(self) -> Iterator[_KT]: ...  # type: ignore
+    def values(self) -> Iterator[_VT]: ...  # type: ignore
+    def items(self) -> Iterator[Tuple[_KT, _VT]]: ...  # type: ignore
     def itervaluerefs(self) -> Iterator[KeyedRef[_KT, _VT]]: ...
     def valuerefs(self) -> List[KeyedRef[_KT, _VT]]: ...
 
@@ -89,32 +74,20 @@ class WeakKeyDictionary(MutableMapping[_KT, _VT]):
     def __getitem__(self, k: _KT) -> _VT: ...
     def __setitem__(self, k: _KT, v: _VT) -> None: ...
     def __delitem__(self, v: _KT) -> None: ...
-    if sys.version_info < (3, 0):
-        def has_key(self, key: object) -> bool: ...
     def __contains__(self, o: object) -> bool: ...
     def __iter__(self) -> Iterator[_KT]: ...
     def __str__(self) -> str: ...
     def copy(self) -> WeakKeyDictionary[_KT, _VT]: ...
-    if sys.version_info >= (3, 0):
-        # These are incompatible with Mapping
-        def keys(self) -> Iterator[_KT]: ...  # type: ignore
-        def values(self) -> Iterator[_VT]: ...  # type: ignore
-        def items(self) -> Iterator[Tuple[_KT, _VT]]: ...  # type: ignore
-    else:
-        def keys(self) -> List[_KT]: ...
-        def values(self) -> List[_VT]: ...
-        def items(self) -> List[Tuple[_KT, _VT]]: ...
-        def iterkeys(self) -> Iterator[_KT]: ...
-        def itervalues(self) -> Iterator[_VT]: ...
-        def iteritems(self) -> Iterator[Tuple[_KT, _VT]]: ...
-        def iterkeyrefs(self) -> Iterator[ref[_KT]]: ...
+    # These are incompatible with Mapping
+    def keys(self) -> Iterator[_KT]: ...  # type: ignore
+    def values(self) -> Iterator[_VT]: ...  # type: ignore
+    def items(self) -> Iterator[Tuple[_KT, _VT]]: ...  # type: ignore
     def keyrefs(self) -> List[ref[_KT]]: ...
 
-if sys.version_info >= (3, 4):
-    class finalize:
-        def __init__(self, __obj: object, __func: Callable[..., Any], *args: Any, **kwargs: Any) -> None: ...
-        def __call__(self, _: Any = ...) -> Optional[Any]: ...
-        def detach(self) -> Optional[Tuple[Any, Any, Tuple[Any, ...], Dict[str, Any]]]: ...
-        def peek(self) -> Optional[Tuple[Any, Any, Tuple[Any, ...], Dict[str, Any]]]: ...
-        alive: bool
-        atexit: bool
+class finalize:
+    def __init__(self, __obj: object, __func: Callable[..., Any], *args: Any, **kwargs: Any) -> None: ...
+    def __call__(self, _: Any = ...) -> Optional[Any]: ...
+    def detach(self) -> Optional[Tuple[Any, Any, Tuple[Any, ...], Dict[str, Any]]]: ...
+    def peek(self) -> Optional[Tuple[Any, Any, Tuple[Any, ...], Dict[str, Any]]]: ...
+    alive: bool
+    atexit: bool