public String toString() {
        return bin_to_hex(this.time_low, 8) + '-' + bin_to_hex(this.time_mid, 4) + '-' + bin_to_hex(this.time_hi_and_version, 4) + '-'
                + bin_to_hex(this.clock_seq_hi_and_reserved, 2) + bin_to_hex(this.clock_seq_low, 2) + '-' + bin_to_hex(this.node[0], 2)
                + bin_to_hex(this.node[1], 2) + bin_to_hex(this.node[2], 2) + bin_to_hex(this.node[3], 2) + bin_to_hex(this.node[4], 2)

    public String toString() {
        return bin_to_hex(time_low, 8) + '-' + bin_to_hex(time_mid, 4) + '-' + bin_to_hex(time_hi_and_version, 4) + '-'
                + bin_to_hex(clock_seq_hi_and_reserved, 2) + bin_to_hex(clock_seq_low, 2) + '-' + bin_to_hex(node[0], 2)
                + bin_to_hex(node[1], 2) + bin_to_hex(node[2], 2) + bin_to_hex(node[3], 2) + bin_to_hex(node[4], 2)
                + bin_to_hex(node[5], 2);
    }