code: public boolean isDecidedOmemoIdentity(OmemoDevice device, OmemoFingerprint fingerprint) {
          if (trustCallback == null) {
              throw new IllegalStateException("No TrustCallback set.");
          }
  
          return trustCallback.getTrust(device, fingerprint) != TrustState.undecided;
      }
docs: Returns true, if the fingerprint/OmemoDevice tuple is decided by the user.
  The fingerprint must be the lowercase, hexadecimal fingerprint of the identityKey of the device and must
  be of length 64.
  @param device device
  @param fingerprint fingerprint
  @return