fix some abstract classes in third_party/ (#1486)

stdlib/3/http/cookiejar.pyi

@@ -1,5 +1,3 @@
-# Stubs for http.cookiejar (Python 3.4)
-
 from typing import Iterable, Iterator, Optional, Sequence, Tuple, TypeVar, Union, overload
 from http.client import HTTPResponse
 import sys
@@ -28,6 +26,7 @@ class CookieJar(Iterable['Cookie']):
               name: str = ...) -> None: ...
     def clear_session_cookies(self) -> None: ...
     def __iter__(self) -> Iterator['Cookie']: ...
+    def __len__(self) -> int: ...
 
 class FileCookieJar(CookieJar):
     filename = ...  # type: str

third_party/2and3/pytz/lazy.pyi

@@ -1,13 +1,14 @@
-# Stubs for pytz.lazy (Python 3.5)
-
-from typing import Any, Iterable, List, Set, Dict  # NOQA
+from typing import Iterator, List, Set, TypeVar
 from collections import Mapping
 
-class LazyDict(Mapping):
-    pass
+_T = TypeVar('_T')
+_KT = TypeVar('_KT')
+_VT = TypeVar('_VT')
 
-class LazyList(List):
-    pass
+class LazyDict(Mapping[_KT, _VT]):
+    def __getitem__(self, key: _KT) -> _VT: ...
+    def __iter__(self) -> Iterator[_KT]: ...
+    def __len__(self) -> int: ...
 
-class LazySet(Set):
-    pass
+class LazyList(List[_T]): ...
+class LazySet(Set[_T]): ...

third_party/2and3/requests/structures.pyi

@@ -1,9 +1,12 @@
-# Stubs for requests.structures (Python 3)
-
 from typing import Any, Iterator, MutableMapping, Text, Tuple, Union
 
 class CaseInsensitiveDict(MutableMapping[str, Union[Text, bytes]]):
     def lower_items(self) -> Iterator[Tuple[str, Union[Text, bytes]]]: ...
+    def __setitem__(self, key: str, value: Union[Text, bytes]) -> None: ...
+    def __getitem__(self, key: str) -> Union[Text, bytes]: ...
+    def __delitem__(self, key: str) -> None: ...
+    def __iter__(self) -> Iterator[str]: ...
+    def __len__(self) -> int: ...
 
 class LookupDict(dict):
     name = ...  # type: Any