diff --git a/TTS/trainer.py b/TTS/trainer.py
index c151e716..b9026c8e 100644
--- a/TTS/trainer.py
+++ b/TTS/trainer.py
@@ -202,7 +202,7 @@ class Trainer:
             os.makedirs(output_path, exist_ok=True)
 
         # copy training assets to the output folder
-        copy_model_files(config, output_path, new_fields=None)
+        copy_model_files(config, output_path)
 
         # init class members
         self.args = args
@@ -274,7 +274,7 @@ class Trainer:
                 self.config.num_languages = self.model.language_manager.num_languages
 
             # update config file
-            copy_model_files(self.config, self.output_path, None)
+            copy_model_files(self.config, self.output_path)
 
         # setup criterion
         self.criterion = self.get_criterion(self.model)
diff --git a/TTS/utils/io.py b/TTS/utils/io.py
index a93f6118..54818ce9 100644
--- a/TTS/utils/io.py
+++ b/TTS/utils/io.py
@@ -26,7 +26,7 @@ class AttrDict(dict):
         self.__dict__ = self
 
 
-def copy_model_files(config: Coqpit, out_path, new_fields):
+def copy_model_files(config: Coqpit, out_path, new_fields=None):
     """Copy config.json and other model files to training folder and add
     new fields.