Developer is a type of Person. Person is related to Voter. Voter is related to Citizen. Civilian is a type of Citizen. 
Session is related to Call. Lift is a type of Call. Lift is a type of Wave. 
Developer --IsA--> Person <--RelatedTo--> Voter <--RelatedTo--> Citizen <--IsA-- Civilian 
Session <--RelatedTo--> Call <--IsA-- Lift --IsA--> Wave 