Support for Prior class in Pydantic models

[williambdean]

The following code:

from pydantic import BaseModel
from pymc_marketing.prior import Prior


class MyParameters(BaseModel):
    beta: Prior
    gamma: Prior

raises the following error:

PydanticSchemaGenerationError: Unable to generate pydantic-core schema for
<class 'pymc_marketing.prior.Prior'>. Set `arbitrary_types_allowed=True` in the
model_config to ignore this error or implement `__get_pydantic_core_schema__`
on your type to fully support it.

If you got this error by calling handler(<some type>) within
`__get_pydantic_core_schema__` then you likely need to call
`handler.generate_schema(<some type>)` since we do not call
`__get_pydantic_core_schema__` on `<some type>` otherwise to avoid infinite
recursion.

For further information visit
https://errors.pydantic.dev/2.10/u/schema-for-unknown-type   gamma: Prior

There is the workaround to use InstanceOf from pydantic

from pydantic import BaseModel, InstanceOf
from pymc_marketing.prior import Prior


class MyParameters(BaseModel):
    beta: InstanceOf[Prior]
    gamma: InstanceOf[Prior]

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This issue was transferred from pymc-labs/pymc-marketing#1247

Comments

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juanitorduz

What would be the usage of this in the code base? Or is it mostly for users to be able to use this?

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williambdean

What would be the usage of this in the code base? Or is it mostly for users to be able to use this?

There are a few times that the InstanceOf[Prior] is used. I am assuming that implementation of that __ method would be a stronger check