refactor: clean up imports and improve code readability in base_chat_step.py

Author: liuruibin

apps/application/chat_pipeline/step/chat_step/impl/base_chat_step.py

@@ -25,7 +25,7 @@
 from application.flow.tools import Reasoning, mcp_response_generator, get_tools
 from application.long_term_memory import extract_long_term_memory
 from application.models import ApplicationChatUserStats, ChatUserType, Application, ApplicationApiKey, \
-    ApplicationAccessToken, ApplicationLongTermMemory, ChatRecord
+    ApplicationAccessToken, ApplicationLongTermMemory
 from common.exception.app_exception import AppApiException
 from common.utils.logger import maxkb_logger
 from common.utils.rsa_util import rsa_long_decrypt
@@ -160,7 +160,6 @@ def event_content(response,
                                                                             'reasoning_content': ''})
 
 
-
 class BaseChatStep(IChatStep):
     def execute(self, message_list: List[BaseMessage],
                 chat_id,
@@ -184,9 +183,10 @@ def execute(self, message_list: List[BaseMessage],
                 skill_tool_ids=None,
                 mcp_output_enable=True,
                 **kwargs):
-        chat_model = get_model_instance_by_model_workspace_id(model_id, workspace_id,
-                                                              **(
-                                                                      model_params_setting or {})) if model_id is not None else None
+        chat_model = get_model_instance_by_model_workspace_id(
+            model_id, workspace_id,
+            **(model_params_setting or {})
+        ) if model_id is not None else None
         if stream:
             return self.execute_stream(message_list, chat_id, problem_text, post_response_handler, chat_model,
                                        paragraph_list,