becomes key in the collisions dictionary the value associated with each bullet is list of aliens it has collided with we loop through the collisions dictionary to make sure we award points for each alien hitgame_ functions py def check_bullet_alien_collisions(ai_settingsscreenstatssbshipaliensbullets)--snip-if collisionsu for aliens in collisions values()stats score +ai_settings alien_points len(alienssb prep_score(--snip-if the collisions dictionary has been definedwe loop through all values in the collisions dictionary remember that each value is list of aliens hit by single bullet we multiply the value of each alien by the number of aliens in each list and add this amount to the current score to test thischange the width of bullet to pixels and verify that you receive points for each alien you hit with your extra wide bulletsthen return the bullet width to normal increasing point values because the game gets more difficult each time player reaches new levelaliens in later levels should be worth more points to implement this functionalitywe'll add code to increase the point value when the game' speed increasessettings py class settings()""" class to store all settings for alien invasion "" def __init__(self)--snip-how quickly the game speeds up self speedup_scale how quickly the alien point values increase self score_scale self initialize_dynamic_settings(def increase_speed(self)"""increase speed settings and alien point values ""self ship_speed_factor *self speedup_scale self bullet_speed_factor *self speedup_scale self alien_speed_factor *self speedup_scale self alien_points int(self alien_points self score_scalewe define rate at which points increasewhich we call score_scale small increase in speed ( makes the game grow challenging quickly