 All the sprites in your big game are now animated, but nothing happens when they run into each other. We're going to use collision detection to find out when sprites have touched each other so that we can later apply rules like increasing or decreasing your score when sprites collide. Using the provided line length function, you will complete a function distance that uses the distance formula to calculate the distance between the center points of two sprites. Next, you'll update the collide function to use the distance function. If the distance between two sprites is less than 100 pixels, the sprites are close enough to be touching, and the collide function should return true. If everything works, you'll see that when the player collides with a target, your score increases, and when the player collides with a danger, your score decreases.