diff --git a/UtilsRL/__init__.py b/UtilsRL/__init__.py
index 6dbe537..a523e0d 100644
--- a/UtilsRL/__init__.py
+++ b/UtilsRL/__init__.py
@@ -1,2 +1,2 @@
 
-__version__ = "0.6.6"
+__version__ = "0.6.7"
diff --git a/UtilsRL/exp/argparse.py b/UtilsRL/exp/argparse.py
index 23c24ac..2a1469e 100644
--- a/UtilsRL/exp/argparse.py
+++ b/UtilsRL/exp/argparse.py
@@ -29,26 +29,15 @@ def get_key(_key):
     else:
         return _key
     
-def parse_cmd_args(convert=True):
+def parse_cmd_args():
     cmd_parser = argparse.ArgumentParser()
     cmd_parser.add_argument("--config", type=str, default=None, help="the path of config file")
     config_args, cmd_args = cmd_parser.parse_known_args()
     num = len(cmd_args)//2
-    cmd_args = dict(zip([get_key(cmd_args[2*i]) for i in range(num)], [cmd_args[2*i+1] for i in range(num)]))
-    args = NameSpace("cmd_args", {}, nested=True) if convert else {}
-    for key, value in cmd_args.items():
-        keys = key.split(".")
-        this = args
-        for subkey in keys[:-1]:
-            if convert:
-                this[subkey] = this.get(subkey, NameSpace(subkey, {}, nested=True))
-            else:
-                this[subkey] = this.get(subkey, {})
-            this = this[subkey]
-        this[keys[-1]] = safe_eval(value)
-    return config_args.config, args
+    cmd_args = dict(zip([get_key(cmd_args[2*i]) for i in range(num)], [safe_eval(cmd_args[2*i+1]) for i in range(num)]))
+    return config_args.config, cmd_args
 
-def parse_file_args(path, convert=True):
+def parse_file_args(path):
     # parse args from config files or modules
     if isinstance(path, str):
         if path.endswith(".json"):
@@ -70,7 +59,6 @@ def parse_file_args(path, convert=True):
     elif path is None:
         file_args = {}
     
-    file_args = NameSpace("args", file_args, nested=True) if convert else file_args
     return file_args
     
 
@@ -103,32 +91,54 @@ def parse_args(
     convert :  Whether or not convert the parse arguments to NameSpace object. 
     """
     
-    cmd_path, cmd_args = parse_cmd_args(convert=convert)
+    cmd_path, cmd_args = parse_cmd_args()
     
-    file_args = parse_file_args(path or cmd_path, convert=convert)
+    file_args = parse_file_args(path or cmd_path)
 
-        
     # update with cmd args
     def traverse_add(old, new, current_key=""):
         for new_key, new_value in new.items():
-            if new_key not in old:
-                logger.warning(f"parse_args: key {current_key + new_key} is not in the config file, setting it to {new_value}")
-                old[new_key] = new_value
-            elif type(old[new_key]) != type(new_value):
-                logger.warning(f"parse_args: overwriting key {current_key + new_key} with {new_value}")
-                old[new_key] = new_value
-            else:
-                if convert and isinstance(new_value, NameSpaceMeta) \
-                    or (not convert and isinstance(new_value, dict)):
-                    traverse_add(old[new_key], new_value, current_key=current_key+new_key+".")
+            this = old
+            keys = new_key.split(".")
+            for kidx, k in enumerate(keys[:-1]):
+                if isinstance(this, list):
+                    # if this is a list, check the key and go to next level
+                    if not (k.isdigit() and int(k)<=len(this)):
+                        logger.error(f"parse_args: {new_key} does not exist.")
+                        raise ValueError(f"parse_args: {new_key} does not exist.")
+                    k = int(k)
+                elif isinstance(this, dict):
+                    # if this is a dict, check the key, add an empty dict if necessary and go to next level
+                    if not k in this.keys():
+                        this[k] = {}
+                if not isinstance(this[k], (dict, list)):
+                    logger.warning(f"parse_args: discarding key {'.'.join(keys[:kidx+1])}")
+                    this[k] = {}
+                this = this[k]
+                
+            # finally, set the value with the last key
+            last_k = keys[-1]
+            if isinstance(this, list):
+                if not (last_k.isdigit() and int(last_k)<=len(this)):
+                    logger.error(f"parse_args: {new_key} does not exist.")
+                    raise ValueError(f"parse_args: {new_key} does not exist.")
+                logger.warning(f"parse_args: overwriting key {new_key} with {new_value}.")
+                this[int(last_k)] = new_value
+            elif isinstance(this, dict):
+                if not last_k in this.keys():
+                    logger.warning(f"parse_args: key {new_key} is not in the config file, setting it to {new_value}.")
+                    this[last_k] = new_value
                 else:
-                    logger.warning(f"parse_args: overwriting key {current_key + new_key} with {new_value}")
-                    old[new_key] = new_value
+                    logger.warning(f"parse_args: overwriting key {new_key} with {new_value}.")
+                    this[last_k] = new_value
                 
     traverse_add(file_args, cmd_args)
     
     if post_init is not None:
         post_init(file_args)
+        
+    if convert:
+       file_args = NameSpace("args", file_args, nested=True)
     
     return file_args