diff --git a/api/controllers/service_api/dataset/rag_pipeline/rag_pipeline_workflow.py b/api/controllers/service_api/dataset/rag_pipeline/rag_pipeline_workflow.py
index cbc1907bf5..f05325d711 100644
--- a/api/controllers/service_api/dataset/rag_pipeline/rag_pipeline_workflow.py
+++ b/api/controllers/service_api/dataset/rag_pipeline/rag_pipeline_workflow.py
@@ -215,7 +215,7 @@ class KnowledgebasePipelineFileUploadApi(DatasetApiResource):
 
         if not file.filename:
             raise FilenameNotExistsError
-        
+
         if not current_user:
             raise ValueError("Invalid user account")
 
diff --git a/api/core/datasource/datasource_manager.py b/api/core/datasource/datasource_manager.py
index 31f982e960..47d297e194 100644
--- a/api/core/datasource/datasource_manager.py
+++ b/api/core/datasource/datasource_manager.py
@@ -84,7 +84,7 @@ class DatasourceManager:
 
         if controller is None:
             raise DatasourceProviderNotFoundError(f"Datasource provider {provider_id} not found.")
-        
+
         return controller
 
     @classmethod
diff --git a/api/core/workflow/nodes/loop/loop_node.py b/api/core/workflow/nodes/loop/loop_node.py
index d783290e51..2b988ad944 100644
--- a/api/core/workflow/nodes/loop/loop_node.py
+++ b/api/core/workflow/nodes/loop/loop_node.py
@@ -92,7 +92,9 @@ class LoopNode(Node):
         if self._node_data.loop_variables:
             value_processor: dict[Literal["constant", "variable"], Callable[[LoopVariableData], Segment | None]] = {
                 "constant": lambda var: self._get_segment_for_constant(var.var_type, var.value),
-                "variable": lambda var: self.graph_runtime_state.variable_pool.get(var.value) if isinstance(var.value, list) else None,
+                "variable": lambda var: self.graph_runtime_state.variable_pool.get(var.value)
+                if isinstance(var.value, list)
+                else None,
             }
             for loop_variable in self._node_data.loop_variables:
                 if loop_variable.value_type not in value_processor: