Fix errors detected by Ruff (#3918)

### What problem does this PR solve?

Fix errors detected by Ruff

### Type of change

- [x] Refactoring

sdk/python/ragflow_sdk/__init__.py

@@ -1,14 +1,21 @@
-from beartype.claw import beartype_this_package
-beartype_this_package()  # <-- raise exceptions in your code
-
 import importlib.metadata
 
-__version__ = importlib.metadata.version("ragflow_sdk")
-
 from .ragflow import RAGFlow
 from .modules.dataset import DataSet
 from .modules.chat import Chat
 from .modules.session import Session
 from .modules.document import Document
 from .modules.chunk import Chunk
-from .modules.agent import Agent
+from .modules.agent import Agent
+
+__version__ = importlib.metadata.version("ragflow_sdk")
+
+__all__ = [
+    "RAGFlow",
+    "DataSet",
+    "Chat",
+    "Session",
+    "Document",
+    "Chunk",
+    "Agent"
+]