package Ġorg . step ik . android . ex ams . data . model Ċ Ċ import Ġorg . step ik . android . ex ams . graph . model . Graph Lesson Ċ import Ġorg . step ik . android . ex ams . graph . model . Topic Ċ Ċ data Ġclass ĠLess on Pract ice Wrapper ( val Ġtopic : ĠTopic , Ġval Ġgraph Lesson : ĠGraph Lesson )