implements single, extends single PASSED!
implements single, extends double PASSED!
implements single, extends single and add PASSED!
implements single, extends triple (extends single and add) PASSED!
implements single, extends double (extends single) PASSED!
implements single, extends double (extends double) PASSED!
implements single, extends double (extends double, extends single and add) PASSED!
implements single, extends double (extends double (extends single), extends single and add) PASSED!
