SEATTLE (AP).- A few lucky visitors first are invited to try on the sorting hat, which compliments them on their bravery, intelligence or cunning. Then, a few steps down a dark corridor, you are surrounded by a cloud of steam. Ahead is the train station, where the Hogworts Express has just arrived. You have entered “Harry Potter: The Exhibition,” a showcase filled with the imagery evoked in J.K. Rowling’s seven-part series about an orphan named Harry who discovers he is part of a mostly hidden magical world. The traveling museum show opens in Seattle on Saturday. What Harry Potter fan hasn’t wanted to sit for a bit in a giant chair at Hagrid’s cottage, watching to see if the dragon’s egg shaking and rattling on the table is going to open? The show also give fans a chance to test their Quidditch skills and see up close the beautiful gowns the actors wore to the Yule Ball in “Harry Potter and the Goblet of Fire.” Costumes and props from the seven movies are in Seattle for an exhi