In UML class diagram notation, how do I denote a top-level function that doesn't have any encapsulating class or other structure?
e.g. I have a function used for retrieving data from a URL. Since it is a function (in the math sense) of only its parameters and a shared global state, the function is not put in a class but left as a top-level method.
Now though, I need to create a UML diagram for a program using it, and I can't find anything about how to denote a top-level function. How do I do this?