Define the initial set of exceptions

Author: ArtyomVancyan

src/fastapi_oauth2/exceptions.py

@@ -1,5 +1,17 @@
 from starlette.exceptions import HTTPException
 
 
-class OAuth2LoginError(HTTPException):
-    """Raised when any login-related error occurs."""
+class OAuth2Error(HTTPException):
+    ...
+
+
+class OAuth2AuthenticationError(OAuth2Error):
+    ...
+
+
+class OAuth2BadCredentialsError(OAuth2Error):
+    ...
+
+
+class OAuth2InvalidRequestError(OAuth2Error):
+    ...