title: Flask-Admin: how to show all fields
body: <p>Well I have different collections (i.e. tables), and they have different columns, say collection <strong>A</strong> has cols a1 and a2, collection <strong>B</strong> has b1 and b2. I want to show all columns</p>
  
  <p>tried following</p>
  
  <pre><code>class UserView(ModelView):
      column_list = None
  </code></pre>
  
  <p>also </p>
  
  <pre><code>column_exclude_list = None
  </code></pre>
  
  <p>getting </p>
  
  <pre><code>NotImplementedError
  </code></pre>
  
  <p>how can I display all fields?</p>
  
  <p>I mean</p>
  
  <pre><code>column_list = ('a1','a2','b1','b2') 
  </code></pre>
  
  <p>works, but I do not want to see empty b1 and b2 fields when looking collection A.</p>