Fix errors detected by Ruff (#3918)

### What problem does this PR solve?

Fix errors detected by Ruff

### Type of change

- [x] Refactoring

api/apps/sdk/agent.py

@@ -14,7 +14,7 @@
 #  limitations under the License.
 #
 
-from api.db.services.canvas_service import CanvasTemplateService, UserCanvasService
+from api.db.services.canvas_service import UserCanvasService
 from api.utils.api_utils import get_error_data_result, token_required
 from api.utils.api_utils import get_result
 from flask import request

api/apps/sdk/doc.py

@@ -41,7 +41,6 @@ from api.utils.api_utils import construct_json_result, get_parser_config
 from rag.nlp import search
 from rag.utils import rmSpace
 from rag.utils.storage_factory import STORAGE_IMPL
-import os
 
 MAXIMUM_OF_UPLOADING_FILES = 256
 
@@ -976,12 +975,12 @@ def add_chunk(tenant_id, dataset_id, document_id):
     if not req.get("content"):
         return get_error_data_result(message="`content` is required")
     if "important_keywords" in req:
-        if type(req["important_keywords"]) != list:
+        if not isinstance(req["important_keywords"], list):
             return get_error_data_result(
                 "`important_keywords` is required to be a list"
             )
     if "questions" in req:
-        if type(req["questions"]) != list:
+        if not isinstance(req["questions"], list):
             return get_error_data_result(
                 "`questions` is required to be a list"
             )

api/apps/sdk/session.py

@@ -143,8 +143,10 @@ def completion(tenant_id, chat_id):
     }
     conv.message.append(question)
     for m in conv.message:
-        if m["role"] == "system": continue
-        if m["role"] == "assistant" and not msg: continue
+        if m["role"] == "system":
+            continue
+        if m["role"] == "assistant" and not msg:
+            continue
         msg.append(m)
     message_id = msg[-1].get("id")
     e, dia = DialogService.get_by_id(conv.dialog_id)
@@ -267,7 +269,8 @@ def agent_completion(tenant_id, agent_id):
         if m["role"] == "assistant" and not msg:
             continue
         msg.append(m)
-    if not msg[-1].get("id"): msg[-1]["id"] = get_uuid()
+    if not msg[-1].get("id"):
+        msg[-1]["id"] = get_uuid()
     message_id = msg[-1]["id"]
 
     stream = req.get("stream", True)
@@ -361,7 +364,8 @@ def agent_completion(tenant_id, agent_id):
         return resp
 
     for answer in canvas.run(stream=False):
-        if answer.get("running_status"): continue
+        if answer.get("running_status"):
+            continue
         final_ans["content"] = "\n".join(answer["content"]) if "content" in answer else ""
         canvas.messages.append({"role": "assistant", "content": final_ans["content"], "id": message_id})
         if final_ans.get("reference"):