Use of MagmaSet ?

[Hilaire Fernandes]

I am using it that way, but something goes wrong as I can not find with 
index and duplication occure on the Set.

Is it the correct way to initialize MagmaSet ? I did not find example of 
use.

Hilaire

    learners := MagmaSet equivalenceAttributes: #(#id).
    learners
       addIndex: ((MaSearchStringIndex attribute: #firstName)
          keySize: 128);
       addIndex: ((MaSearchStringIndex attribute: #lastName)
          keySize: 128);
       addIndex: (MaIntegerIndex attribute: #id).