我正在尝试绘制svm，但每次遇到此错误 “ plot.svm（Linearclassifier，training_set）中的错误：缺少公式。 调用：SVM_Function-> plot-> plot.svm“
Linearclassifier = svm(formula = diagnosis ~ ., data = training_set, type
= 'C-classification', kernel = 'linear')
Linearprediction = predict(Linearclassifier, newdata = testing_set[-1])
plot(Linearclassifier,training_set )