(Turtle: draw a regular polygon) Write the following function to draw a regular polygon:
def drawPolygon $(x=0, y=0, \text { radius }=50, \text { number0fSides }=3):$
The polygon is centered at $(x, y)$ with a specified radius for the bounding circle for the polygon and the number of sides. Write a test program that displays a triangle, square, pentagon, hexagon, heptagon, and octagon, as shown in Figure $6.12 \mathrm{a}$.