[Pharo-users] question re. meaning of 'self' in a method used for testing

Hi—I’m a beginner in Pharo and am working my way through Pharo by Example 5.0 (PbE) and Learning OOP and TDD with Pharo (LOTWP). I’m currently going through 7.4 Designing a test, in LOTWP, which covers testing whether a string has no repeated characters, adding the method String >> isIsogramSet. GramCheckerTest, a class for testing, has the following methods: — isograms "list of isograms; used for testing" ^ #('pharo' 'pathfinder' 'xavier' 'lumberjacks’) testAllIsogramSet "using each word in list named 'isograms'" self isograms do: [ :word | self assert: word isIsogramSet ] — Here are my questions: 1) These two methods are defined on the instance side (the Class button is *not* selected). If so, what is the receiver when they are used? 2) In testAllIsogramSet, why do you need ‘self’? After all ‘isograms’ is a data structure, and its message is ‘do:’ 3) As an add-on to 2), what does ‘self’ refer to? The class GramCheckerTest? If so, wouldn’t that make testAllIsogramSet a class method? But testAllIsogramSet doesn’t appear in the class browser when I click the Class button when the Class pane shows GramCheckerTest. Thanks for any help you might give/point me to regarding this.