(Tkinter: insertion-sort animation) Write a program that animates the insertion-sort algorithm. Create a list that consists of 20 distinct numbers from 1 to 20 in a random order. The elements are displayed in a histogram, as shown in Figure 10.21. Clicking the Step button causes the program to perform an iteration of the outer loop in the algorithm and repaints the histogram for the new list. Color the last bar in the sorted sublist. When the algorithm is finished, display a dialog box to inform the user. Clicking the Reset button creates a new random list for a new start.

FIGURE 10.21 The program animates an insertion sort.