How to handle multiple pydantic response in fast api

Describe the bug

When using Union on response_model, it doesn’t return accurate result To Reproduce

Create three models

from pydantic import BaseModel

   class parent(BaseModel):
       id: str

   class child1(parent):
      code: str
      user: Any

  class child2(parent):
    `error:` Any

class child3(parent):
 code: str
 user_data: Any

Add it on response_model

     from typing import Union
    from fastapi import APIRouter

    router = APIRouter()

   @router.post('/verify', response_model=Union[child1, child3,child2])
   async def something(some: some):
      dict1 = {
          "id": 1,
          "code" : "213",
          "user":{'id':"123","pass":"pass"}
          }
      dict2 = {
          "id": 1,
          "error" : "213"
         }
       dict3 = {
          "id": 1,
          "code" : "213",
          "user_data":{'id':"123","pass":"pass"}
         }
       
     if cond1 :  
          return child1(**dict1).dict()
    elif cond2 :  
          return child2(**dict2).dict()
     else:
         return child3(**dict3).dict()

output actual :
On running all the condition one by one output that i got is not correct when cond 1 gets true then

      {
        "id": 1,
         "code" : "213",
         "user":{'id':"123","pass":"pass"}
        }

when cond 2 gets true then

{
       "id": 1,
        "error" : "213"
       }

when cond 3 gets true then

{
     "id": 1,
      "code" : "213"
     }

Expected behavior

cond 1 and 2 output are correct but cond3 is incorrect i want cond3 output to have user_data field as below

{
        "id": 1,
         "code" : "213"
       "user_data":{'id':"123","pass":"pass"}
        }

how can i get the output to have all the fields of dict3

i am new to fast api and can anyone help me with this issue, any resolution to this issue or any other way to get the expected output with schema in swagger UI

Additional Info: What i observed here is Field type: Any has issue , as when i specify the field to str or dict , it gives the correct output as expected

[Rushyanth111]

Currently, it is a known missing feature within the Swagger UI (See: #1083 ) and the generation of the example cannot be automatically done by Swagger UI, however it is possible to provide a manual example, which would mean that you have to make an example to be displayed.

Link to the Relevant Issue Solution from #1083

Link to Another Solution from #86

The Example Shows you that you need to provide a manual example like so:

Create A Class that holds the Union of any of the three Classes:

class parent(BaseModel):
    id: str


class child1(parent):
    code: str
    user: Dict[str, str]


class child2(parent):
    error: Any


class child3(parent):
    code: str
    user_data: Dict[str, str]


class UnionChild(BaseModel): # This will Hold the Union
    Child: Union[child1, child2, child3] #The Union Required

    class Config: #This is inside UnionChild, do not place it outside. 
        schema_extra = {
            "example": {                    #Mandatory field, this holds your example. Define Your Field from here. 
                "id": "1",
                "error": "Some Random String",
                "user": "OSAS UVUWE",
                "user_data": {"oh": "oh_no"},
            }
        }


app = FastAPI()


@app.get("/verify", response_model=UnionChild)
async def something(some: int):
    pass

[gunjeetgulatigit]

Thanks @Rushyanth111