Removed imported symbols that are not accessed or re-exported (#4387)

Co-authored-by: Eric Traut <erictr@microsoft.com>

stdlib/3/dbm/__init__.pyi

@@ -1,4 +1,3 @@
-import sys
 from types import TracebackType
 from typing import Iterator, MutableMapping, Optional, Type, Union
 from typing_extensions import Literal

stdlib/3/dbm/dumb.pyi

@@ -1,12 +1,6 @@
-import sys
 from types import TracebackType
 from typing import Iterator, MutableMapping, Optional, Type, Union
 
-if sys.version_info >= (3, 8):
-    from typing import Final
-else:
-    from typing_extensions import Final
-
 _KeyType = Union[str, bytes]
 _ValueType = Union[str, bytes]
 

stdlib/3/dbm/gnu.pyi

@@ -1,5 +1,5 @@
 from types import TracebackType
-from typing import Generic, Iterator, List, Optional, Type, TypeVar, Union, overload
+from typing import List, Optional, Type, TypeVar, Union, overload
 
 _T = TypeVar("_T")
 _KeyType = Union[str, bytes]

stdlib/3/dbm/ndbm.pyi

@@ -1,5 +1,5 @@
 from types import TracebackType
-from typing import Generic, Iterator, List, Optional, Type, TypeVar, Union, overload
+from typing import List, Optional, Type, TypeVar, Union, overload
 
 _T = TypeVar("_T")
 _KeyType = Union[str, bytes]