While my condo's maintenance head was looking under my kitchen sink (on a different matter), he pointed out that my faucet hose was not connected directly to the valve. He said it's illegal but he did add later that he wasn't sure.

My faucet hose-extension tube-valve looks like this:

I live in Chicago, in a high-rise condo. My question is, does it violate a particular Chicago building/plumbing code for a kitchen faucet hose to be connected to a valve via an extension tube?

I would like to know which particular item in the Chicago/Illinois plumbing code states how a faucet hose should or should not be connected to a valve. Please pardon my silly question. I find navigating through the Chicago/Illinois plumbing code quite confusing.