def _rfe_single_fit(rfe, estimator, X, y, train, test, scorer):
 (X_train, y_train) = _safe_split(estimator, X, y, train)
 (X_test, y_test) = _safe_split(estimator, X, y, test, train)
 return rfe._fit(X_train, y_train, (lambda estimator, features: _score(estimator, X_test[:, features], y_test, scorer))).scores_

def _rfe_single_fit ( rfe , estimator , X , y , train , test , scorer ) : ( X_train , y_train ) = _safe_split ( estimator , X , y , train ) ( X_test , y_test ) = _safe_split ( estimator , X , y , test , train ) return rfe . _fit ( X_train , y_train , ( lambda estimator , features : _score ( estimator , X_test [ : , features ] , y_test , scorer ) ) ) . scores_
return the score for a fit across one fold .