I am new to Bokeh and I would really appreciate some help in figuring out how to use Bokeh to plot a simple interactive pie chart in Jupyer/Python. I am planning to use 'CustomJS with a Python function' in Bokeh as explained at the bottom of the page here. The pie chart consists of two entries with a slider that can change the shape of one pie 'v2' inside the circle shape of (v1+v2). I have tried to follow the example in bokeh website that shows the interactivity with a sine plot, but I just cannot get it to work with my pie chart. Any help would be greatly appreciated. Below is the code block I am using inside a Jupyter notebook.
import numpy as np
import matplotlib.pyplot as plt
from bokeh.layouts import column
from bokeh.models import CustomJS, ColumnDataSource, Slider
from bokeh.plotting import Figure, output_file, show, output_notebook
from bokeh.charts import Donut, show
#output_file('donut.html')
output_notebook()
v1=1
v2=.2
import pandas as pd
data = pd.Series([v1,v2], index = list('ab'))
plot = Figure(plot_width=400, plot_height=400)
plot = Donut(data)
def pie_chart(source=data,window=None,deltav=None):
data = source.data
v2 = deltav.value
#v2 = data['v2']
source.trigger('change')
slider = Slider(start=.1, end=1., value=.2, step=.1, title="delta-V", callback=CustomJS.from_py_func(pie_chart))
callback.args["deltav"] = slider
l = column(slider, plot)
show(l)
