the for loop on line adjusts the alpha value for the color used for each frame of animation (increasing at firstand then decreasingconverting from pixel coordinates to buttons def getbuttonclicked(xy) if yellowrect collidepoint(xy) return yellow elif bluerect collidepoint(xy) return blue elif redrect collidepoint(xy) return red elif greenrect collidepoint(xy) return green return none if __name__ ='__main__' main(the getbuttonclicked(function simply takes xy pixel coordinates and returns either the values yellowblueredor green if one of the buttons was clickedor returns none if the xy pixel coordinates are not over any of the four buttons explicit is better than implicit you may have noticed that the code for getbuttonclicked(ends with return none statement on line this might seem like an odd thing to type outsince all functions return none if they don' have any return statement at all we could have left line out entirely and the program would have worked the exact same way so why bother writing it innormally when function reaches the end and returns the none value implicitly (that isthere is no return statement outright saying that it is returning nonethe code that calls it doesn' care about the return value all function calls have to return value (so that they can evaluate to something and be part of expressions)but our code doesn' always make use of the return value for examplethink about the print(function technicallythis function returns the none valuebut we never care about itspam print('hello'hello spam =none true