chore: import upstream snapshot with attribution

docs_src/session_groups/tutorial003.py

@@ -0,0 +1,19 @@
+import asyncio
+
+from mcp import ClientSessionGroup, StdioServerParameters
+
+
+async def main() -> None:
+    library = StdioServerParameters(command="uv", args=["run", "mcp", "run", "library_server.py"])
+    web = StdioServerParameters(command="uv", args=["run", "mcp", "run", "web_server.py"])
+
+    async with ClientSessionGroup() as group:
+        await group.connect_to_server(library)
+        await group.connect_to_server(web)
+
+        result = await group.call_tool("search", {"query": "model context protocol"})
+        print(result.structured_content)
+
+
+if __name__ == "__main__":
+    asyncio.run(main())