clean python 3 specific stuff from stdlib/@python2 stubs (#5451)

stdlib/@python2/pickle.pyi

@@ -2,53 +2,12 @@ import sys
 from typing import IO, Any, Callable, Iterable, Iterator, Mapping, Optional, Tuple, Type, Union
 
 HIGHEST_PROTOCOL: int
-if sys.version_info >= (3, 0):
-    DEFAULT_PROTOCOL: int
-
 bytes_types: Tuple[Type[Any], ...]  # undocumented
 
-if sys.version_info >= (3, 8):
-    # TODO: holistic design for buffer interface (typing.Buffer?)
-    class PickleBuffer:
-        # buffer must be a buffer-providing object
-        def __init__(self, buffer: Any) -> None: ...
-        def raw(self) -> memoryview: ...
-        def release(self) -> None: ...
-    _BufferCallback = Optional[Callable[[PickleBuffer], Any]]
-    def dump(
-        obj: Any,
-        file: IO[bytes],
-        protocol: Optional[int] = ...,
-        *,
-        fix_imports: bool = ...,
-        buffer_callback: _BufferCallback = ...,
-    ) -> None: ...
-    def dumps(
-        obj: Any, protocol: Optional[int] = ..., *, fix_imports: bool = ..., buffer_callback: _BufferCallback = ...
-    ) -> bytes: ...
-    def load(
-        file: IO[bytes],
-        *,
-        fix_imports: bool = ...,
-        encoding: str = ...,
-        errors: str = ...,
-        buffers: Optional[Iterable[Any]] = ...,
-    ) -> Any: ...
-    def loads(
-        __data: bytes, *, fix_imports: bool = ..., encoding: str = ..., errors: str = ..., buffers: Optional[Iterable[Any]] = ...
-    ) -> Any: ...
-
-elif sys.version_info >= (3, 0):
-    def dump(obj: Any, file: IO[bytes], protocol: Optional[int] = ..., *, fix_imports: bool = ...) -> None: ...
-    def dumps(obj: Any, protocol: Optional[int] = ..., *, fix_imports: bool = ...) -> bytes: ...
-    def load(file: IO[bytes], *, fix_imports: bool = ..., encoding: str = ..., errors: str = ...) -> Any: ...
-    def loads(data: bytes, *, fix_imports: bool = ..., encoding: str = ..., errors: str = ...) -> Any: ...
-
-else:
-    def dump(obj: Any, file: IO[bytes], protocol: Optional[int] = ...) -> None: ...
-    def dumps(obj: Any, protocol: Optional[int] = ...) -> bytes: ...
-    def load(file: IO[bytes]) -> Any: ...
-    def loads(string: bytes) -> Any: ...
+def dump(obj: Any, file: IO[bytes], protocol: Optional[int] = ...) -> None: ...
+def dumps(obj: Any, protocol: Optional[int] = ...) -> bytes: ...
+def load(file: IO[bytes]) -> Any: ...
+def loads(string: bytes) -> Any: ...
 
 class PickleError(Exception): ...
 class PicklingError(PickleError): ...
@@ -64,46 +23,15 @@ _reducedtype = Union[
 
 class Pickler:
     fast: bool
-    if sys.version_info >= (3, 3):
-        dispatch_table: Mapping[type, Callable[[Any], _reducedtype]]
-
-    if sys.version_info >= (3, 8):
-        def __init__(
-            self,
-            file: IO[bytes],
-            protocol: Optional[int] = ...,
-            *,
-            fix_imports: bool = ...,
-            buffer_callback: _BufferCallback = ...,
-        ) -> None: ...
-        def reducer_override(self, obj: Any) -> Any: ...
-    elif sys.version_info >= (3, 0):
-        def __init__(self, file: IO[bytes], protocol: Optional[int] = ..., *, fix_imports: bool = ...) -> None: ...
-    else:
-        def __init__(self, file: IO[bytes], protocol: Optional[int] = ...) -> None: ...
+    def __init__(self, file: IO[bytes], protocol: Optional[int] = ...) -> None: ...
     def dump(self, __obj: Any) -> None: ...
     def clear_memo(self) -> None: ...
     def persistent_id(self, obj: Any) -> Any: ...
 
 class Unpickler:
-    if sys.version_info >= (3, 8):
-        def __init__(
-            self,
-            file: IO[bytes],
-            *,
-            fix_imports: bool = ...,
-            encoding: str = ...,
-            errors: str = ...,
-            buffers: Optional[Iterable[Any]] = ...,
-        ) -> None: ...
-    elif sys.version_info >= (3, 0):
-        def __init__(self, file: IO[bytes], *, fix_imports: bool = ..., encoding: str = ..., errors: str = ...) -> None: ...
-    else:
-        def __init__(self, file: IO[bytes]) -> None: ...
+    def __init__(self, file: IO[bytes]) -> None: ...
     def load(self) -> Any: ...
     def find_class(self, __module_name: str, __global_name: str) -> Any: ...
-    if sys.version_info >= (3, 0):
-        def persistent_load(self, pid: Any) -> Any: ...
 
 MARK: bytes
 STOP: bytes
@@ -164,23 +92,5 @@ NEWFALSE: bytes
 LONG1: bytes
 LONG4: bytes
 
-if sys.version_info >= (3, 0):
-    # protocol 3
-    BINBYTES: bytes
-    SHORT_BINBYTES: bytes
-
-if sys.version_info >= (3, 4):
-    # protocol 4
-    SHORT_BINUNICODE: bytes
-    BINUNICODE8: bytes
-    BINBYTES8: bytes
-    EMPTY_SET: bytes
-    ADDITEMS: bytes
-    FROZENSET: bytes
-    NEWOBJ_EX: bytes
-    STACK_GLOBAL: bytes
-    MEMOIZE: bytes
-    FRAME: bytes
-
 def encode_long(x: int) -> bytes: ...  # undocumented
 def decode_long(data: bytes) -> int: ...  # undocumented