code: public Set<OmemoDevice> getDevicesOf(BareJid contact) {
          OmemoCachedDeviceList list = getOmemoService().getOmemoStoreBackend().loadCachedDeviceList(getOwnDevice(), contact);
          HashSet<OmemoDevice> devices = new HashSet<>();
  
          for (int deviceId : list.getActiveDevices()) {
              devices.add(new OmemoDevice(contact, deviceId));
          }
  
          return devices;
      }
docs: Return a set of all OMEMO capable devices of a contact.
  Note, that this method does not explicitly refresh the device list of the contact, so it might be outdated.
  @see #requestDeviceListUpdateFor(BareJid)
  @param contact contact we want to get a set of device of.
  @return set of known devices of that contact.