Class variables define get-behaviour and can be accessed using the normal get/[3-13] call. Class variables are the last type of behaviour checked when resolving a get-method. Below are the most commonly used methods to access class-variables.
<-type' if the value is written. Writing class-variables should be handled with care, as existing instances of the class are not notified of the change, and may not be prepared deal with changes of the class-variable value. pce_image_directory/1 is an example of a predicate modifying the image.path class-variable.