docs: private Set<OmemoDevice> getUndecidedDevices(OmemoDevice userDevice, OmemoTrustCallback callback, Set<OmemoDevice> devices) {
          Set<OmemoDevice> undecidedDevices = new HashSet<>();
  
          for (OmemoDevice device : devices) {
  
              OmemoFingerprint fingerprint;
              try {
                  fingerprint = getOmemoStoreBackend().getFingerprint(userDevice, device);
              } catch (CorruptedOmemoKeyException | NoIdentityKeyException e) {
                  // TODO: Best solution?
                  LOGGER.log(Level.WARNING, "Could not load fingerprint of " + device, e);
                  undecidedDevices.add(device);
                  continue;
              }
  
              if (callback.getTrust(device, fingerprint) == TrustState.undecided) {
                  undecidedDevices.add(device);
              }
          }
  
          return undecidedDevices;
      }