diff --git a/hydrolib/core/io/rtc/basemodel.py b/hydrolib/core/io/rtc/basemodel.py
index bcf49f8e3..e085b04b7 100644
--- a/hydrolib/core/io/rtc/basemodel.py
+++ b/hydrolib/core/io/rtc/basemodel.py
@@ -1,11 +1,15 @@
 from pydantic.class_validators import root_validator
 from hydrolib.core.basemodel import BaseModel
-from typing import Any, get_origin
+from typing import get_origin
 from hydrolib.core.utils import to_list
+from pydantic.fields import ModelField
 
 class RtcBaseModel(BaseModel):
     @root_validator(pre=True)
     def validate(cls, data) -> dict:
+        if not isinstance(data, dict):
+            return data
+    
         data = cls._get_root_data(data)
         data = cls._get_list_data(data)
 
@@ -36,11 +40,37 @@ def _get_list_data(cls, data: dict) -> dict:
         for key, value in data.items():
 
             field = cls.__fields__.get(key)
-            field_type = field.outer_type_ # returns e.g. List[str] or Optional[List[str]]
-            non_generic_field_type = get_origin(field_type) or field_type.__origin__ # returns e.g. list
+            if not field:
+                continue
 
-            if non_generic_field_type is list:
+            field_type = cls._get_field_type(field)
+
+            if field_type is list:
                 data[key] = to_list(value)
 
         return data
 
+    @classmethod
+    def _get_field_type(cls, field: ModelField):
+        """Gets the non-generic field type of a model field.
+        For example, if the model field type is `List[str]`, 
+        the returned type will be `list`.
+
+        Args:
+            field (ModelField): The model field.
+
+        Returns:
+            The non-generic type of the model field for example `list`.
+        """
+        # `outer_type_` returns e.g. List[str]
+        field_type = field.outer_type_
+
+        # `origin` returns e.g. list
+        origin =  get_origin(field_type)
+        if origin:
+            return origin
+        
+        if hasattr(field_type, "__origin__"):
+            return field_type.__origin__
+
+        return None