# skfolio.utils.tools.check_estimator ### skfolio.utils.tools.check_estimator(estimator, default, check_type) Check the estimator type and return its cloned version if provided, otherwise return the default estimator. * **Parameters:** **estimator** *BaseEstimator | “passthrough”, optional* : Estimator. **default** *BaseEstimator, optional* : Default estimator to return when `estimator` is `None`. **check_type** *Any* : Expected type of the estimator to check against. * **Returns:** **estimator** *Estimator | “passthrough”* : The checked estimator or the default.