如何更新holoviews使用ipywidgets SelectionRangeSlider的酒吧？

我想通过SelectionRangeSlider从Jupyter笔记本中的某些熊猫DataFrame中选择数据，并使用holoviews条形图绘制过滤的数据。如何更新holoviews使用ipywidgets SelectionRangeSlider的酒吧？

请看下面的例子：

import numpy as np 
import pandas as pd 
import datetime 
import holoviews as hv 
hv.extension('bokeh') 

import ipywidgets as widgets 

start = int(datetime.datetime(2017,1,1).strftime("%s")) 
end = int(datetime.datetime(2017,12,31).strftime("%s")) 

size = 100 
rints = np.random.randint(start, end + 1, size = size) 
df = pd.DataFrame(rints, columns = ['zeit']) 
df["bytes"] = np.random.randint(5,20,size=size) 
df['who']= np.random.choice(['John', 'Paul', 'George', 'Ringo'], len(df)) 
df["zeit"] = pd.to_datetime(df["zeit"], unit='s') 
df.zeit = df.zeit.dt.date 

df.sort_values('zeit', inplace = True) 
df = df.reset_index(drop=True) 
df.head(2)

这使测试数据框df：

让我们组数据：

data = pd.DataFrame(df.groupby('who')['bytes'].sum()) 
data.reset_index(level=0, inplace=True) 
data.sort_values(by="bytes", inplace=True) 
data.head(2)

现在，创建要用于过滤和更新条形图的SelectionRangeSlider。

%%opts Bars [width=800 height=400 tools=['hover']] 
def view2(v): 
    x = df[(df.zeit > r2.value[0].date()) & (df.zeit < r2.value[1].date())] 
    data = pd.DataFrame(x.groupby('who')['bytes'].sum()) 
    data.sort_values(by="bytes", inplace=True) 
    data.reset_index(inplace=True) 
    display(hv.Bars(data, kdims=['who'], vdims=['bytes'])) 

r2 = widgets.SelectionRangeSlider(options = options, index = index, description = 'Test') 
widgets.interactive(view2, v=r2)