why use "be of something", is there some meaning for this "of"?

Question

I saw a sentence when reading some technical articles:>When we call this function, it expects the second parameter to be of type Collection. The actual argument is of type Collection.So my question is why use "of" in this sentence? Does it change some meaning for this sentence? Can I delete the "of" and directly say, "The actual argument is type Collection"?

Answer 1

To "be of" means to be a product of something or to belong to something. If you change the wording, you have to be careful to retain the meaning.