public boolean revokeOldKey(@NonNull final NetworkKey networkKey) {
        if (netKeys.contains(networkKey)) {
            return networkKey.revokeOldKey();
        }
        return false;
    }
Revokes the old key.
<p>
This initiates {@link KeyRefreshPhase#REVOKE_OLD_KEYS} of the Key Refresh Procedure in which user must send {@link ConfigKeyRefreshPhaseSet}
message with transition set to {@link KeyRefreshPhaseTransition#REVOKE_OLD_KEYS} to the other nodes going through the Key Refresh Procedure.
The library at this point will set the given Network Key's Phase to {@link KeyRefreshPhase#NORMAL_OPERATION}.
</p>

@param networkKey Network key that was distributed
@return true if success or false otherwise
mesh/src/main/java/no/nordicsemi/android/mesh/BaseMeshNetwork.java