{
  rich {
    university_dept_DeptHeads {
      findHeadByName {
        invoke(name: "Prof. Dicky Horwich") {
          results {
            changeName {
              invokeIdempotent(newName: "Prof. Dicky Horwich!") {
                results {
                  name {
                    get
                  }
                }
              }
            }
          }
        }
      }
    }
  }
}
