Add class description comments

Author: ArtyomVancyan

src/fastapi_oauth2/client.py

@@ -6,6 +6,8 @@
 
 
 class OAuth2Client:
+    """OAuth2 client configuration for a single provider."""
+
     backend: Type[BaseOAuth2]
     client_id: str
     client_secret: str

src/fastapi_oauth2/config.py

@@ -6,6 +6,8 @@
 
 
 class OAuth2Config:
+    """Configuration class of the authentication middleware."""
+
     allow_http: bool
     jwt_secret: str
     jwt_expires: int

src/fastapi_oauth2/core.py

@@ -20,12 +20,12 @@
 
 
 class OAuth2LoginError(HTTPException):
-    """Raised when any login-related error occurs
-    (such as when user is not verified or if there was an attempt for fake login)
-    """
+    """Raised when any login-related error occurs."""
 
 
 class OAuth2Strategy(BaseStrategy):
+    """Dummy strategy for using the `BaseOAuth2.user_data` method."""
+
     def request_data(self, merge=True):
         return {}