@NonNull
    public static Parameters extend(@Nullable final Parameters params, final String... keyValues) {
        return params == null ? new Parameters(keyValues) : params.put(keyValues);
    }
Extend or create a Parameters object with new key/value pairs.

@param params    an existing object or null to create a new one
@param keyValues list of key/value pair
@return the object itself if it is non-null, a new one otherwise
@throws InvalidParameterException if the number of key/values is unbalanced
main/src/main/java/cgeo/geocaching/network/Parameters.java