Internal method for checking that the selected inference scheme is compatible with the specified model

def _check_inference(self, inference):
        """
        Internal method for checking that the selected inference scheme is compatible with the specified model
        """
        if inference=='GP2KronSum':
            assert self.n_randEffs==2, 'VarianceDecomposition: for fast inference number of random effect terms must be == 2'
            assert not sp.isnan(self.Y).any(), 'VarianceDecomposition: fast inference available only for complete phenotype designs'