How do I remove the duplicated code for this code sample?
<p>Given the following code:</p>

<pre><code>public interface DTMFKeys {

    public String getKeyStr();

    public static enum Sign implements TahoeDTMFKeys {

        SIGN_1("*1"), SIGN_2("*2"), SING_3("*3"), SIGN_4("*4"), SIGN_5("*5"), SIGN_6(
                "*6"), SIGN_7("*7"), SIGN_8("*8"), SIGN_9("*9");

        private String keyStr;

        private Sign(String keyStr) {
            this.keyStr = keyStr;
        }

        @Override
        public String getKeyStr() {
            return keyStr;
        }
    }

    public static enum Pound implements TahoeDTMFKeys {

        POUND_1("1#"), POUND_2("2#"), POUND_3("3#"), POUND_4("4#"), POUND_5(
                "5#"), POUND_6("6#"), POUND_7("7#"), POUND_8("8#"), POUND_9(
                "9#");

        private String keyStr;

        private Pound(String keyStr) {
            this.keyStr = keyStr;
        }

        @Override
        public String getKeyStr() {
            return keyStr;
        }
    }
}
</code></pre>

<p>How do I remove the duplicated code:</p>

<pre><code>private Sign(String keyStr){
    this.keyStr=keyStr;
}

@Override
public String getKeyStr() {
    return keyStr;
}
</code></pre>
