Childrens book ideas?! 10 pts.?

I have to write a childrens book for some first graders. The book has to be about how a bill becomes a law. But i'm not sure what kinda story line or theme of characters i should use. I was wanting to use something from disney. But i can't think of anything...i'm not a political person so idk..Plz help and give me some good ideas.