refactor: improve type hints and formatting in keyring provider

Author: putradimas

pydantic_settings/sources/providers/keyring.py

@@ -1,4 +1,5 @@
-from typing import TYPE_CHECKING, Mapping
+from collections.abc import Mapping
+from typing import TYPE_CHECKING
 
 from pydantic_settings import BaseSettings, EnvSettingsSource
 
@@ -7,7 +8,7 @@
 else:
     keyring = None
 
-def import_keyring():
+def import_keyring() -> None:
     global keyring
     if keyring is not None:
         return
@@ -16,7 +17,7 @@ def import_keyring():
 
         return
     except ImportError as e:
-        raise ImportError("Keyring is not installed, run `pip install keyring`") from e
+        raise ImportError('Keyring is not installed, run `pip install keyring`') from e
 
 
 class KeyringConfigSettingsSource(EnvSettingsSource):
@@ -40,7 +41,7 @@ def _load_env_vars(self) -> Mapping[str, str | None]:
         prefix = self.env_prefix
         if not self.case_sensitive:
                 prefix = self.env_prefix.lower()
-        env_vars = {}
+        env_vars: dict[str, str | None] = {}
         for field in self.settings_cls.model_fields.keys():
             if not self.case_sensitive:
                 field = field.lower()
@@ -54,9 +55,9 @@ def _load_env_vars(self) -> Mapping[str, str | None]:
         return env_vars
 
     def __repr__(self) -> str:
-        return f"{self.__class__.__name__}(keyring_service={self.keyring_service})"
+        return f'{self.__class__.__name__}(keyring_service={self.keyring_service})'
 
 
 __all__ = [
-    "KeyringConfigSettingsSource",
+    'KeyringConfigSettingsSource',
 ]