title: Error when using mice object: No applicable method for 'complete_'
body: <pre class="lang-r prettyprint-override"><code>library(mice)
  md.pattern(dat1)
  temp&lt;-mice(dat1, m = 5, seed = 101)
  dat1 &lt;- complete(temp, 2)
  </code></pre>
  <blockquote>
  <p>Error in UseMethod(&quot;complete_&quot;) :<br />
  no applicable method for 'complete_' applied to an object of class &quot;mids&quot;</p>
  </blockquote>
  <p>Hi, I'm trying to impute missing values using <code>mice</code> package.
  But I got the above error message.
  The first time I imputed missing data it worked, but when I tried again it didn't. I've tried a lot with different options (changing seed, deleting existing data or &quot;temp&quot; variable)</p>
  <p>Sometimes it worked but other times it didn't.
  What is the problem and solution?
  Thanks in advance.</p>