### Question:
OmemoService implements OmemoCarbonCopyStanzaReceivedListener, OmemoMessageStanzaReceivedListener { static void removeOurDevice(OmemoDevice userDevice, Collection<OmemoDevice> devices) { if (devices.contains(userDevice)) { devices.remove(userDevice); } } protected  OmemoService(); static OmemoService<?, ?, ?, ?, ?, ?, ?, ?, ?> getInstance(); static boolean isServiceRegistered(); OmemoStore<T_IdKeyPair, T_IdKey, T_PreKey, T_SigPreKey, T_Sess, T_Addr, T_ECPub, T_Bundle, T_Ciph> getOmemoStoreBackend(); @SuppressWarnings("unused") void setOmemoStoreBackend(
            OmemoStore<T_IdKeyPair, T_IdKey, T_PreKey, T_SigPreKey, T_Sess, T_Addr, T_ECPub, T_Bundle, T_Ciph> omemoStore); @Override void onOmemoCarbonCopyReceived(CarbonExtension.Direction direction,
                                          Message carbonCopy,
                                          Message wrappingMessage,
                                          OmemoManager.LoggedInOmemoManager managerGuard); @Override void onOmemoMessageStanzaReceived(Stanza stanza, OmemoManager.LoggedInOmemoManager managerGuard); void purgeDeviceList(OmemoManager.LoggedInOmemoManager managerGuard);  }### Answer:
@Test public void removeOurDeviceTest() throws XmppStringprepException { OmemoDevice a = new OmemoDevice(JidCreate.bareFrom("a@b.c"), 123); OmemoDevice b = new OmemoDevice(JidCreate.bareFrom("a@b.c"), 124); HashSet<OmemoDevice> devices = new HashSet<>(); devices.add(a); devices.add(b); assertTrue(devices.contains(a)); assertTrue(devices.contains(b)); OmemoService.removeOurDevice(a, devices); assertFalse(devices.contains(a)); assertTrue(devices.contains(b)); }