Python callback for sorted bars in a bar chart

How to convert below into a Python callback? Basically, how to incorporate the “sorted_fruits” into source that is updated with callback function?

from import output_file, show
from bokeh.plotting import figure


fruits = ['Apples', 'Pears', 'Nectarines', 'Plums', 'Grapes', 'Strawberries']
counts = [5, 3, 4, 2, 4, 6]

# sorting the bars means sorting the range factors
sorted_fruits = sorted(fruits, key=lambda x: counts[fruits.index(x)])

p = figure(x_range=sorted_fruits, plot_height=350, title="Fruit Counts",
           toolbar_location=None, tools="")

p.vbar(x=fruits, top=counts, width=0.9)

p.xgrid.grid_line_color = None
p.y_range.start = 0