if TYPE_CHECKING:
    ...

    # 1. RunSpanData and friends are pydantic models. RunSpanData.params is
    #    typed as InferenceRequestParams.
    # 2. InferenceRequestParams.sampling (and other fields) have
    #    a ModelProviderDefault annotation.
    # 3. ModelProviderDefault is a plain setinel class that causes pydantic to
    #    freak out when building a schema.

    # also, importing without a guard would cause a circular import
    # in models/core/api.py
    _InferenceParams = params_.InferenceRequestParams
    _GenerateParams = params_.GenerateParams
else:
    _InferenceParams = Any
    _GenerateParams = Any