标注不会出现在带有组的python bokeh条形图中

from bokeh.io import output_file, show
from bokeh.models import ColumnDataSource, LabelSet
from bokeh.plotting import figure

# 创建数据
data = {
    'groups': ['A', 'B', 'C'],
    'values': [10, 20, 30]
}

# 创建ColumnDataSource
source = ColumnDataSource(data)

# 创建绘图对象
p = figure(x_range=data['groups'], plot_height=400, title='Grouped Bar Chart')

# 绘制条形图
p.vbar(x='groups', top='values', width=0.9, source=source)

# 创建标签
labels = LabelSet(x='groups', y='values', text='values', level='glyph',
                  x_offset=-13.5, y_offset=0, source=source, render_mode='canvas')

# 添加标签到绘图对象
p.add_layout(labels)

# 输出到HTML文件并显示
output_file('grouped_bar_chart.html')
show(p)