python缺少1个必需的位置参数

Question

这是一个创建分类器的简单ML程序。我是按照ML上的Google开发者播放列表创建的。当我运行程序时，输出错误（TypeError：fit（）缺少1个必需的位置参数：“ y_train”）。我不知道这怎么可能。from scipy.spatial import distancedef euc(a,b):    return distance.euclidean(a,b)class ScrappyKNN():    def fit(self,X_train,y_train):        self.X_train=X_train        self.Y_train=y_train    def predict(self,X_test):        predictions=[]        for row in X_test:            label = self.closest(row)            predictions.append(label)        return predictions    def closest(self,row):        best_dist = euc(row,self.X_train[0])        best_index=0        for i in range(1,len(self.X_train)):            dist= euc(row,self.X_train[i])            if dist>best_dist:                best_dist=dist                best_index=i        return self.Y_train[best_index]from sklearn import datasetsfrom sklearn.cross_validation import train_test_splitfrom sklearn.metrics import accuracy_scoreiris = datasets.load_iris()X=iris.datay=iris.targetX_train, X_test, y_train, y_test=train_test_split(X,y,test_size=0.5)my_classifier=ScrappyKNNmy_classifier.fit(X_train, y_train)   predictions=my_classifier.predict(X_test)print(accuracy_score(y_test,predictions))