aliensin this we'll add aliens to alien invasion firstwe'll add one alien near the top of the screenand then we'll generate whole fleet of aliens we'll make the fleet advance sideways and downand we'll get rid of any aliens hit by bullet finallywe'll limit the number of ships player has and end the game when the player runs out of ships as you work through this you'll learn more about pygame and about managing larger project you'll also learn to detect collisions between game objectslike bullets and aliens detecting collisions helps you define interactions between elements in your gamesyou can confine character inside the walls of maze or pass ball between two characters we'll also continue to work from plan that we revisit occasionally to maintain the focus of our code-writing sessions before we start writing new code to add fleet of aliens to the screenlet' look at the project and update our plan