I use pydantic 2.5.3.

Here my code

from pydantic import BaseModel

class A(BaseModel):
    a: float = 0.0

When I do

a = A()
a.model_dump_json(serialize_as_any = True)

I got an error

        a = A()
>       a.model_dump_json(serialize_as_any = False)
E       TypeError: BaseModel.model_dump_json() got an unexpected keyword argument 'serialize_as_any'

but according documentation it should work

Maybe I miss something?