title: How to replace the old weka api Instance.missingValue()?
body: <p>I had developed a project using the old version weka jar about 4 years ago, and there was  one sentence <code>Instance.missingValue()</code> as I have replaced  the old weka jar file with the newest version, the IDE gives the error </p>
  
  <blockquote>
    <p>can not resolve the method missingValue. </p>
  </blockquote>
  
  <p>I have read the api document of weka and found that the Instance class have been revised to the interface, but how to change the sentence <code>Instance.missingValue()</code>?</p>