The class Pizza draws a pizza chart.
serie, chart_size, legend_color, legend_title_rayon, legend_value_rayon and chart_border are properties, they could be changed dynamically.
Example ::
pie = Pizza(serie=[
["Français", 5, 'a9a9a9'],
["Belge", 25, '808080'],
["Anglais", 20, '696969'],
["Allemand", 30, '778899'],
["Italien", 20, '708090']],
chart_size=256,
legend_color='ffffcc',
legend_value_rayon=100,
legend_title_rayon=160,
chart_border=2)