Fix errors detected by Ruff (#3918)

### What problem does this PR solve?

Fix errors detected by Ruff

### Type of change

- [x] Refactoring

sdk/python/test/test_frontend_api/common.py

@@ -39,7 +39,6 @@ def update_dataset(auth, json_req):
 def upload_file(auth, dataset_id, path):
     authorization = {"Authorization": auth}
     url = f"{HOST_ADDRESS}/v1/document/upload"
-    base_name = os.path.basename(path)
     json_req = {
         "kb_id": dataset_id,
     }

sdk/python/test/test_frontend_api/get_email.py

@@ -1,3 +1,3 @@
 def test_get_email(get_email):
-    print(f"\nEmail account:",flush=True)
+    print("\nEmail account:",flush=True)
     print(f"{get_email}\n",flush=True)

sdk/python/test/test_frontend_api/test_chunk.py

@@ -13,14 +13,10 @@
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
 
-from common import HOST_ADDRESS, create_dataset, list_dataset, rm_dataset, update_dataset, upload_file, DATASET_NAME_LIMIT
+from common import create_dataset, list_dataset, rm_dataset, upload_file
 from common import list_document, get_docs_info, parse_docs
 from time import sleep
 from timeit import default_timer as timer
-import re
-import pytest
-import random
-import string
 
 
 def test_parse_txt_document(get_auth):

sdk/python/test/test_frontend_api/test_dataset.py

@@ -1,6 +1,5 @@
-from common import HOST_ADDRESS, create_dataset, list_dataset, rm_dataset, update_dataset, DATASET_NAME_LIMIT
+from common import create_dataset, list_dataset, rm_dataset, update_dataset, DATASET_NAME_LIMIT
 import re
-import pytest
 import random
 import string
 
@@ -33,8 +32,6 @@ def test_dataset(get_auth):
 
 def test_dataset_1k_dataset(get_auth):
     # create dataset
-    authorization = {"Authorization": get_auth}
-    url = f"{HOST_ADDRESS}/v1/kb/create"
     for i in range(1000):
         res = create_dataset(get_auth, f"test_create_dataset_{i}")
         assert res.get("code") == 0, f"{res.get('message')}"
@@ -76,7 +73,7 @@ def test_duplicated_name_dataset(get_auth):
         dataset_id = item.get("id")
         dataset_list.append(dataset_id)
         match = re.match(pattern, dataset_name)
-        assert match != None
+        assert match is not None
 
     for dataset_id in dataset_list:
         res = rm_dataset(get_auth, dataset_id)