Use of と and や when listing several items

[gasuton]

Hi,
I am going through Japanese for busy people, Book 1, lesson 8 and I have a question on the use of と and や. Suppose we have the question

かばんの なかに かぎ や ほん が あります -(1)

My question is, that I though where the や is we could use と. Is my understanding incorrect, and using と in (1) would just be wrong?

Thanks for your help!!!
Tony

 

[Toritoribe]

や is used for inexhaustive lists, so your example sentence connotes that there are some other goods in the bag other than a key and a book.