In Pharo 9, how do I create a package that has a hierarchy of sub-packages like in "Announcements-Core" where there is an expanding and collapsing arrow?
I thought that it might be based on the names of the packages but when I tried with the following messages to create two classes they just show up as separate packages. What I want is for there to be a package "T-base" that has sub packages "type1" and "type2"?
Object subclass: #T1 instanceVariableNames: '' classVariableNames: '' package: 'T-base-type1'
Object subclass: #T2 instanceVariableNames: '' classVariableNames: '' package: 'T-base-type2'

