diff --git a/vnpy_hts/api/generator/generate_api_functions.py b/vnpy_hts/api/generator/generate_api_functions.py
index 99509ee..43bb0df 100644
--- a/vnpy_hts/api/generator/generate_api_functions.py
+++ b/vnpy_hts/api/generator/generate_api_functions.py
@@ -175,7 +175,7 @@ def generate_source_task(self):
                         f.write("\t{\n")
                         f.write(f"\t\t{type_} *task_error = new {type_}();\n")
                         f.write(f"\t\t*task_error = *{field};\n")
-                        f.write(f"\t\ttask.task_error = task_error;\n")
+                        f.write("\t\ttask.task_error = task_error;\n")
                         f.write("\t}\n")
                     else:
                         if not field:
@@ -185,10 +185,10 @@ def generate_source_task(self):
                         f.write("\t{\n")
                         f.write(f"\t\t{type_} *task_data = new {type_}();\n")
                         f.write(f"\t\t*task_data = *{field};\n")
-                        f.write(f"\t\ttask.task_data = task_data;\n")
+                        f.write("\t\ttask.task_data = task_data;\n")
                         f.write("\t}\n")
 
-                f.write(f"\tthis->task_queue.push(task);\n")
+                f.write("\tthis->task_queue.push(task);\n")
                 f.write("};\n\n")
 
     def generate_source_switch(self):
@@ -200,7 +200,7 @@ def generate_source_switch(self):
                 f.write(f"case {name.upper()}:\n")
                 f.write("{\n")
                 f.write(f"\tthis->{process_name}(&task);\n")
-                f.write(f"\tbreak;\n")
+                f.write("\tbreak;\n")
                 f.write("}\n\n")
 
     def generate_source_process(self):
@@ -283,7 +283,7 @@ def generate_source_function(self):
                     if struct_type == "string":
                         line = f"\tgetString(req, \"{struct_field}\", myreq.{struct_field});\n"
                     elif struct_type == "int":
-                        if struct_field == "requestID" or struct_field == "localOrderID"or struct_field == "sessionID":
+                        if struct_field == "requestID" or struct_field == "localOrderID" or struct_field == "sessionID":
                             line = f"\tgetInt(req, \"{struct_field}\", &myreq.{struct_field});\n"
                         else:
                             line = f"\tget{struct_type.capitalize()}(req, \"{struct_field}\", &myreq.{struct_field});\n"
@@ -329,7 +329,7 @@ def generate_source_on(self):
                 f.write("\t}\n")
                 f.write("\tcatch (const error_already_set &e)\n")
                 f.write("\t{\n")
-                f.write(f"\t\tcout << e.what() << endl;\n")
+                f.write("\t\tcout << e.what() << endl;\n")
                 f.write("\t}\n")
                 f.write("};\n\n")