The function cleans the utility expression by removing extra white spaces, removes brackets and other information to return a clean, easy-to-read expression.
An object of class utility
A cleaned utility function as a list
We can also use the side-effect of the function on a list of utility expressions that do not contain brackets to return a an updated utility expression with alternative specific attribute names.
Warning: The function does not check if the utility expression *is* clean,
which means that running the function multiple times will result in
duplicate alternative names for the attributes. You need to pay particular
attention to this fact when using the formula
because this function calls