title: WTForms FieldList with optional fields
body: <p>I have the following form,</p>
  
  <pre><code>class AddForm(wtf.Form):
      tags = TagListField("Tags (comma separated)", validators=[wtf.Required()])
      question = wtf.TextField("Question", validators=[wtf.Required()])
      answers = wtf.FieldList(wtf.TextField("Answer", validators=[wtf.Required()]), min_entries=2, max_entries=5)
  </code></pre>
  
  <p>And I have a form setup to display this form along with a button that adds more "answers" inputs dynamically (by the user clicking a button). However, when the form gets submitted, any fields that are added but not filled in are considered errors.</p>
  
  <p>Specifically, if I have 3 inputs for "Answer", but I only fill in the first two, then the third one comes up as an error, even though I have specified that the minimum number of entries is 2. It seems like it should ignore this data.</p>
  
  <p>Since I am using this with <a href="http://flask.pocoo.org" rel="nofollow">Flask</a> I am going to just modify the <code>request.form</code> data to ignore blank fields. Is there something I'm missing?</p>