Changed the error message in case of a nomination_id not being supplied ...

...in the run method. Some documentation for the most important methods. Moved URL strings to constants at the top of the file.
Oh man, you are totally right -- I remember reading that "gotcha" somewhere, now that you mention it. OK, so this is a :+1: for merge, then, and after that the `options={}` in the method signature should change to just `options`.