Stubtest fixes (#5249)

stdlib/collections/__init__.pyi

@@ -1,5 +1,5 @@
 import sys
-from typing import Any, Dict, Generic, List, Optional, Tuple, Type, TypeVar, Union, overload
+from typing import Any, Dict, Generic, List, NoReturn, Optional, Tuple, Type, TypeVar, Union, overload
 
 if sys.version_info >= (3, 10):
     from typing import (
@@ -190,7 +190,6 @@ class deque(MutableSequence[_T], Generic[_T]):
     def __len__(self) -> int: ...
     def __iter__(self) -> Iterator[_T]: ...
     def __str__(self) -> str: ...
-    def __hash__(self) -> int: ...
     # These methods of deque don't really take slices, but we need to
     # define them as taking a slice to satisfy MutableSequence.
     @overload
@@ -222,6 +221,8 @@ class Counter(Dict[_T, int], Generic[_T]):
     def copy(self: _S) -> _S: ...
     def elements(self) -> Iterator[_T]: ...
     def most_common(self, n: Optional[int] = ...) -> List[Tuple[_T, int]]: ...
+    @classmethod
+    def fromkeys(cls, iterable: Any, v: Optional[int] = ...) -> NoReturn: ...  # type: ignore
     @overload
     def subtract(self, __iterable: None = ...) -> None: ...
     @overload
@@ -291,10 +292,9 @@ class defaultdict(Dict[_KT, _VT], Generic[_KT, _VT]):
     def copy(self: _S) -> _S: ...
 
 class ChainMap(MutableMapping[_KT, _VT], Generic[_KT, _VT]):
+    maps: List[Mapping[_KT, _VT]]
     def __init__(self, *maps: Mapping[_KT, _VT]) -> None: ...
-    @property
-    def maps(self) -> List[Mapping[_KT, _VT]]: ...
-    def new_child(self, m: Mapping[_KT, _VT] = ...) -> ChainMap[_KT, _VT]: ...
+    def new_child(self, m: Optional[Mapping[_KT, _VT]] = ...) -> ChainMap[_KT, _VT]: ...
     @property
     def parents(self) -> ChainMap[_KT, _VT]: ...
     def __setitem__(self, k: _KT, v: _VT) -> None: ...