如何使用Python matplotlib在两个条形图中生成相同的颜色？

import matplotlib.pyplot as plt
import numpy as np

categories = ['A', 'B', 'C', 'D', 'E']
values1 = [20, 35, 30, 35, 27]
values2 = [25, 32, 34, 20, 25]

plt.bar(categories, values1, color='red', alpha=0.7)
plt.bar(categories, values2, color='red', alpha=0.3)

plt.title('Comparison of Values')
plt.xlabel('Categories')
plt.ylabel('Values')

plt.show()