Modify the template you created in Ex:WikipediaLinkTemplate so that if the articleName variable is not defined, the article name will instead be taken from the articlename field of the current tiddler.

Tip: The else filter operator, which adds a constant string to the pipeline if there are no input tiddlers, will be useful here. You will also need to put !is[blank] before the else operator – we'll explain why once you've completed this exercise.