def _validate_estimator(self, default=None):
        """Check the value of alpha and beta and clustering algorithm.
        """
        check_parameter(self.alpha, low=0, high=1, param_name='alpha',
                        include_left=False, include_right=False)

        check_parameter(self.beta, low=1, param_name='beta',
                        include_left=False)

        if self.clustering_estimator is not None:
            self.clustering_estimator_ = self.clustering_estimator
        else:
            self.clustering_estimator_ = default

        # make sure the base clustering algorithm is valid
        if self.clustering_estimator_ is None:
            raise ValueError("clustering algorithm cannot be None")

        if self.check_estimator:
            check_estimator(self.clustering_estimator_)
Check the value of alpha and beta and clustering algorithm.
        
pyod/models/cblof.py