Remove Python 3.7 branches (#11238)

stdlib/csv.pyi

@@ -24,16 +24,12 @@ from _csv import (
 
 if sys.version_info >= (3, 12):
     from _csv import QUOTE_NOTNULL as QUOTE_NOTNULL, QUOTE_STRINGS as QUOTE_STRINGS
+
 from _typeshed import SupportsWrite
 from collections.abc import Collection, Iterable, Iterator, Mapping, Sequence
 from typing import Any, Generic, TypeVar, overload
 from typing_extensions import Literal, Self
 
-if sys.version_info >= (3, 8):
-    from builtins import dict as _DictReadMapping
-else:
-    from collections import OrderedDict as _DictReadMapping
-
 if sys.version_info >= (3, 12):
     from types import GenericAlias
 
@@ -69,7 +65,7 @@ class excel(Dialect): ...
 class excel_tab(excel): ...
 class unix_dialect(Dialect): ...
 
-class DictReader(Iterator[_DictReadMapping[_T | Any, str | Any]], Generic[_T]):
+class DictReader(Iterator[dict[_T | Any, str | Any]], Generic[_T]):
     fieldnames: Sequence[_T] | None
     restkey: _T | None
     restval: str | Any | None
@@ -113,7 +109,7 @@ class DictReader(Iterator[_DictReadMapping[_T | Any, str | Any]], Generic[_T]):
         strict: bool = False,
     ) -> None: ...
     def __iter__(self) -> Self: ...
-    def __next__(self) -> _DictReadMapping[_T | Any, str | Any]: ...
+    def __next__(self) -> dict[_T | Any, str | Any]: ...
     if sys.version_info >= (3, 12):
         def __class_getitem__(cls, item: Any) -> GenericAlias: ...
 
@@ -139,11 +135,7 @@ class DictWriter(Generic[_T]):
         quoting: _QuotingType = 0,
         strict: bool = False,
     ) -> None: ...
-    if sys.version_info >= (3, 8):
-        def writeheader(self) -> Any: ...
-    else:
-        def writeheader(self) -> None: ...
-
+    def writeheader(self) -> Any: ...
     def writerow(self, rowdict: Mapping[_T, Any]) -> Any: ...
     def writerows(self, rowdicts: Iterable[Mapping[_T, Any]]) -> None: ...
     if sys.version_info >= (3, 12):