Display data in (%) for pie chart using the PyChart library in Python

I am creating a pie chart using PyChart library in Python. Here is my code:

from pychart import *
import sys

data = [("foo", 10), ("bar", 20), ("baz", 30), ("ao", 40)]
theme.use_color = True
theme.get_options()

ar = area.T(size = (150, 150), legend = legend.T(),
            x_grid_style = None, y_grid_style = None)

plot = pie_plot.T(data = d开发者_运维知识库ata, arc_offsets = [0, 0, 0, 0], label_offset = 20, arrow_style = arrow.a3)
ar.add_plot(plot)
ar.draw()

How can I display data in (%) on this pie chart?

Would converting the data to percentages before passing it to the plot function work?

For example:

def to_percents(data):
    total = float(sum(v for _, v in data))
    data[:] = [(k, v / total) for k, v in data]
    return data

data = to_percents([("foo", 1), ("bar", 3), ("baz", 5), ("ao", 7)])
print data

Output:

[('foo', 0.0625), ('bar', 0.1875), ('baz', 0.3125), ('ao', 0.4375)]