Remove Python 3.7 branches (#11238)

stdlib/concurrent/futures/__init__.pyi

@@ -1,5 +1,3 @@
-import sys
-
 from ._base import (
     ALL_COMPLETED as ALL_COMPLETED,
     FIRST_COMPLETED as FIRST_COMPLETED,
@@ -8,6 +6,7 @@ from ._base import (
     CancelledError as CancelledError,
     Executor as Executor,
     Future as Future,
+    InvalidStateError as InvalidStateError,
     TimeoutError as TimeoutError,
     as_completed as as_completed,
     wait as wait,
@@ -15,9 +14,6 @@ from ._base import (
 from .process import ProcessPoolExecutor as ProcessPoolExecutor
 from .thread import ThreadPoolExecutor as ThreadPoolExecutor
 
-if sys.version_info >= (3, 8):
-    from ._base import InvalidStateError as InvalidStateError
-
 __all__ = (
     "FIRST_COMPLETED",
     "FIRST_EXCEPTION",

stdlib/concurrent/futures/_base.pyi

@@ -30,9 +30,7 @@ if sys.version_info >= (3, 11):
 else:
     class TimeoutError(Error): ...
 
-if sys.version_info >= (3, 8):
-    class InvalidStateError(Error): ...
-
+class InvalidStateError(Error): ...
 class BrokenExecutor(RuntimeError): ...
 
 _T = TypeVar("_T")