title: Want to plot a decision tree in R got this error: (sapply(split, tail, 1) %in% mf_levels[[var_id]]) is not TRUE
body: <p>I use J48 to generate a decision tree below, when I want to plot it by using</p>
  
  <pre><code>if(require("party",quietly=TRUE)) plot(fit_1)
  </code></pre>
  
  <p>it gives an error:</p>
  
  <blockquote>
    <p>Error: all(sapply(split, tail, 1) %in% mf_levels[[var_id]]) is not TRUE</p>
  </blockquote>
  
  <p>what does this error mean?</p>