Feat/assistant app (#2086)

Co-authored-by: chenhe <guchenhe@gmail.com>
Co-authored-by: Pascal M <11357019+perzeuss@users.noreply.github.com>

api/core/tools/entities/common_entities.py

@@ -0,0 +1,22 @@
+from typing import Optional
+
+from pydantic import BaseModel
+
+
+class I18nObject(BaseModel):
+    """
+    Model class for i18n object.
+    """
+    zh_Hans: Optional[str] = None
+    en_US: str
+
+    def __init__(self, **data):
+        super().__init__(**data)
+        if not self.zh_Hans:
+            self.zh_Hans = self.en_US
+
+    def to_dict(self) -> dict:
+        return {
+            'zh_Hans': self.zh_Hans,
+            'en_US': self.en_US,
+        }