diff --git a/backend-flask/spec.py b/backend-flask/spec.py
index 40401f8..779ce3c 100644
--- a/backend-flask/spec.py
+++ b/backend-flask/spec.py
@@ -24,4 +24,4 @@ class BaseModel(pydantic.v1.BaseModel):
     class Config:
         alias_generator = to_camel
         allow_population_by_field_name = True
-
+        smart_union = True