Python 具有多个组的条形图的不同y标度

我在matplotlib分的条形图中有两组，测量结果不同.我希望右边的那个有一个单独的y轴，以免相对于左边的那个看起来收缩.这就是我到目前为止try 过的:

代码 :

import numpy as np
import matplotlib.pyplot as plt

plt.rcParams['figure.dpi'] = 300
plt.rcParams['font.size'] = 14

# set width of bars
barWidth = 0.15

bars1   = [10, 0.5]
bars2   = [11, 0.8]
bars3   = [20, 1.0]
bars4   = [30, 1.5]
bars5   = [40, 1.8]

# Set position of bar on X axis
r1 = np.arange(len(bars1))
r2 = [x + barWidth for x in r1]
r3 = [x + barWidth for x in r2]
r4 = [x + barWidth for x in r3]
r5 = [x + barWidth for x in r4]

# Make the plot
fig, ax = plt.subplots(figsize=(8, 6))
ax.bar(r1, bars1, color='#7f6d5f', width=barWidth, edgecolor='white')
ax.bar(r2, bars2, color='#557f2d', width=barWidth, edgecolor='white')
ax.bar(r3, bars3, color='#2d7f5e', width=barWidth, edgecolor='white')
ax.bar(r4, bars4, color='#2d7f5e', width=barWidth, edgecolor='white')
ax.bar(r5, bars5, color='#2d7f5e', width=barWidth, edgecolor='white')

# Create secondary y-axis for the right group
ax2 = ax.twinx()
ax2.set_ylabel('scale2', fontweight='bold', labelpad=10)

group_labels = ['group1', 'group2']
ax.set_xlabel('Datasets', fontweight='bold', labelpad=10)
ax.set_ylabel('scale1', fontweight='bold', labelpad=10,)
ax.set_xticks([r + 2 * barWidth for r in range(len(bars1))])
ax.set_xticklabels(group_labels)

ax.spines['right'].set_visible(False)
ax.spines['top'].set_visible(False)
plt.show()

当前输出:

我怎样才能让group2只受到scale2的影响？