如何在sklearn.metrics包中更改plot_confusion_matrix默认图形大小

import matplotlib.pyplot as plt
from sklearn.metrics import plot_confusion_matrix
from sklearn.datasets import load_iris
from sklearn.model_selection import train_test_split
from sklearn.svm import SVC

# 加载数据集
iris = load_iris()
X, y = iris.data, iris.target

# 划分训练集和测试集
X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42)

# 训练模型
model = SVC()
model.fit(X_train, y_train)

# 创建混淆矩阵图
fig, ax = plt.subplots(figsize=(8, 6))  # 设置图形大小为8x6

# 绘制混淆矩阵
plot_confusion_matrix(model, X_test, y_test, ax=ax)

# 显示图形
plt.show()