Is it possible to import to the global scope from inside a function (Python)?

I am trying to import a module from inside a function and have it be available to my whole file the same way it would be if I imported outside any functions and before all the other code. The reason it is in a function is because I don't have much control over the structure of the script. Is this possible without resorting to things like hacking __builtin__ or passing what I need all around my code?