'Aux function.'

@verbose
def _check_n_pca_components(self, _n_pca_comp, verbose=None):

    if isinstance(_n_pca_comp, float):
        _n_pca_comp = ((self.pca_explained_variance_ / self.pca_explained_variance_.sum()).cumsum() <= _n_pca_comp).sum()
        logger.info(('Selected    %i    PCA    components    by    explained    variance' % _n_pca_comp))
    elif (_n_pca_comp is None):
        _n_pca_comp = self.max_pca_components
    elif (_n_pca_comp < self.n_components_):
        _n_pca_comp = self.n_components_
    return _n_pca_comp
