我正在尝试使用matplotlib在时间序列数据集上绘制特定日期。这些日期表示我想突出显示的一些事件。我想对多个日期进行此操作。我可以对一个日期进行此操作，但不能对多个日期进行此操作。有人能帮助我绘制多个日期吗？

from datetime import datetime
from matplotlib.dates import date2num

fig, ax = plt.subplots(figsize=(30,10))
ax.plot(df)
ax.axvspan(date2num(datetime(2022,4,8)), date2num(datetime(2022,4,8)), 
           label="Leaks",color="red", alpha=1)
ax.legend()
ax.set_ylabel('Values')
ax.set_title('Leaks in liquid Lvl', size=28)

我试过几种方法，但都不管用。

from datetime import datetime
from matplotlib.dates import date2num
from matplotlib.dates import date3num
from matplotlib.dates import date4num

fig, ax = plt.subplots(figsize=(30,10))
ax.plot(df)

ax.axvspan(date2num(datetime(2022,4,8)), date2num(datetime(2022,4,8)), date3num(datetime(2022,6,22)), date3num(datetime(2022,6,22)),date4num(datetime(2022,9,2)), date4num(datetime(2022,9,2)),
           label="Leaks",color="red", alpha=1)

ax.legend()
ax.set_ylabel('Values')
ax.set_title('Leaks in liquid Lvl', size=28)

###############################################

from datetime import datetime
from matplotlib.dates import date2num
from matplotlib.dates import date3num
from matplotlib.dates import date4num

fig, ax = plt.subplots(figsize=(30,10))
ax.plot(df)
#ax.axvspan(date2num(datetime(2022,4,8)), date2num(datetime(2022,4,8)), 
           #label="Leaks",color="red", alpha=1)
#ax.axvspan(date3num(datetime(2022,6,22)), date3num(datetime(2022,6,22)), 
           #label="Leaks",color="red", alpha=1)
#ax.axvspan(date4num(datetime(2022,9,2)), date4num(datetime(2022,9,2)), 
           #label="Leaks",color="red", alpha=1)

ax.legend()
ax.set_ylabel('Values')
ax.set_title('Leaks in liquid Lvl', size=28)