Arrgh, no! In order to start this lesson properly, let's formulate it the positive way: Please use positive identifiers! Why? Is it just another instance of the 'think positive' way of live?No! It's simply that boolean variables can have value
Admittedly, after a bit of thinking you find it out. But compare it with the positive formulation and you will see, that this is really easier to understand:
skipIntro=False -> performIntro=True omitRules=False -> includeRules=True suppressWarning=False -> showWarning=True
The same applies to checkmarks in GUIs. Sometimes GUI designers seem to like to name the checkmarks in a way that the default mark status is 'deselected'. I think it is much better to name a checkmark such that the base case is associated with 'deselected' and 'selected' is reserved for switching a feature on, also if the default is that the feature is on.