chore: apply and fix flake8-bugbear lint rules (#4496)

api/core/model_runtime/callbacks/base_callback.py

@@ -1,4 +1,3 @@
-from abc import ABC
 from typing import Optional
 
 from core.model_runtime.entities.llm_entities import LLMResult, LLMResultChunk
@@ -14,7 +13,7 @@ _TEXT_COLOR_MAPPING = {
 }
 
 
-class Callback(ABC):
+class Callback:
     """
     Base class for callbacks.
     Only for LLM.

api/core/tools/tool_manager.py

@@ -361,7 +361,6 @@ class ToolManager:
 
             :return: the label of the tool
         """
-        cls._builtin_tools_labels
         if len(cls._builtin_tools_labels) == 0:
             # init the builtin providers
             cls.load_builtin_providers_cache()

api/core/workflow/nodes/tool/tool_node.py

@@ -39,7 +39,6 @@ class ToolNode(BaseNode):
         parameters = self._generate_parameters(variable_pool, node_data)
         # get tool runtime
         try:
-            self.app_id
             tool_runtime = ToolManager.get_workflow_tool_runtime(self.tenant_id, self.app_id, self.node_id, node_data)
         except Exception as e:
             return NodeRunResult(