Update comments (#4569)

### What problem does this PR solve?

Add license statement.

### Type of change

- [x] Refactoring

Signed-off-by: Jin Hai <haijin.chn@gmail.com>

sdk/python/test/test_sdk_api/t_chat.py

@@ -1,6 +1,23 @@
+#
+#  Copyright 2025 The InfiniFlow Authors. All Rights Reserved.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+
 from ragflow_sdk import RAGFlow
 from common import HOST_ADDRESS
 
+
 def test_create_chat_with_name(get_api_key_fixture):
     API_KEY = get_api_key_fixture
     rag = RAGFlow(API_KEY, HOST_ADDRESS)
@@ -8,10 +25,10 @@ def test_create_chat_with_name(get_api_key_fixture):
     display_name = "ragflow.txt"
     with open("test_data/ragflow.txt", "rb") as file:
         blob = file.read()
-    document = {"display_name":display_name,"blob":blob}
+    document = {"display_name": display_name, "blob": blob}
     documents = []
     documents.append(document)
-    docs= kb.upload_documents(documents)
+    docs = kb.upload_documents(documents)
     for doc in docs:
         doc.add_chunk("This is a test to add chunk")
     rag.create_chat("test_create_chat", dataset_ids=[kb.id])
@@ -50,6 +67,7 @@ def test_delete_chats_with_success(get_api_key_fixture):
     chat = rag.create_chat("test_delete_chat", dataset_ids=[kb.id])
     rag.delete_chats(ids=[chat.id])
 
+
 def test_list_chats_with_success(get_api_key_fixture):
     API_KEY = get_api_key_fixture
     rag = RAGFlow(API_KEY, HOST_ADDRESS)
@@ -66,5 +84,3 @@ def test_list_chats_with_success(get_api_key_fixture):
     rag.create_chat("test_list_1", dataset_ids=[kb.id])
     rag.create_chat("test_list_2", dataset_ids=[kb.id])
     rag.list_chats()
-
-