Adding tags to Tkinter canvas items

Is there a particular method for adding tags to a given canvas item in Tkinter? It sounds ridiculous, there's an addtag_*() method for virtually everything but I can't find one that will just accept an item number and append the given tag to it. There's even an addtag() function but the __doc__ string simply states that it's an 'Internal function'.

So... is there some cleverly hidden function to do this? Or am I gonna have to piss about with gettag() and itemconfig() to retrieve, append, and then change the tags manually?