lint: Drop special-case imports for Python < 3.8

src/mbedtls/_tls.pyi

@@ -5,9 +5,8 @@ from __future__ import annotations
 
 import enum
 import os
-import sys
 from collections import abc
-from typing import Optional, Sequence, Tuple, Union, overload
+from typing import Literal, Optional, Sequence, Tuple, Union, overload
 
 from mbedtls._tlsi import (
     Certificate,
@@ -17,11 +16,6 @@ from mbedtls._tlsi import (
     TLSVersion,
 )
 
-if sys.version_info < (3, 8):
-    from typing_extensions import Literal
-else:
-    from typing import Literal
-
 _VERSION = Tuple[int, int]
 
 def ciphers_available() -> Sequence[str]: ...

src/mbedtls/mpi.pyi

@@ -4,13 +4,7 @@
 from __future__ import annotations
 
 import numbers
-import sys
-from typing import Any, NoReturn, Optional, Tuple, Union, overload
-
-if sys.version_info < (3, 8):
-    from typing_extensions import Literal
-else:
-    from typing import Literal
+from typing import Any, Literal, NoReturn, Optional, Tuple, Union, overload
 
 _Integral = Union[numbers.Integral, int]
 

src/mbedtls/pk.pyi

@@ -9,6 +9,8 @@ import os
 import sys
 from typing import (
     Callable,
+    Final,
+    Literal,
     NamedTuple,
     NoReturn,
     Optional,
@@ -19,11 +21,6 @@ from typing import (
     overload,
 )
 
-if sys.version_info < (3, 8):
-    from typing_extensions import Final, Literal
-else:
-    from typing import Final, Literal
-
 if sys.version_info < (3, 9):
     _Path = Union[os.PathLike, str]  # type: ignore [type-arg]
 else:

src/mbedtls/version.pyi

@@ -3,13 +3,7 @@
 
 from __future__ import annotations
 
-import sys
-from typing import NamedTuple
-
-if sys.version_info < (3, 8):
-    from typing_extensions import Final
-else:
-    from typing import Final
+from typing import Final, NamedTuple
 
 class mbedtls_version(NamedTuple):
     major: int

src/mbedtls/x509.pyi

@@ -7,17 +7,11 @@ import abc
 import datetime as dt
 import enum
 import os
-import sys
-from typing import NamedTuple, Sequence, Tuple, Type, TypeVar, Union
+from typing import Literal, NamedTuple, Sequence, Tuple, Type, TypeVar, Union
 
 from mbedtls.hashlib import Hash as _Hash
 from mbedtls.pk import ECC, RSA
 
-if sys.version_info < (3, 8):
-    from typing_extensions import Literal
-else:
-    from typing import Literal
-
 _Path = Union[str, os.PathLike[str]]
 _DER = bytes
 _PEM = str