title: Rendering a WTForms CheckboxInput in Jinja Template
body: <p>I can't seem to figure out how to render a WTForms <code>CheckboxInput</code> in my template.  When I try to render the field using Flask in my Jinja template I get this error:</p>
  
  <p>TypeError: <strong>call</strong>() takes exactly 2 arguments (1 given)</p>
  
  <p>The error has to do with how <code>{{ form.prefs(value='n') }}</code> is used in my template.  The WTForms documentation for <a href="http://wtforms.simplecodes.com/docs/0.6/widgets.html#wtforms.widgets.CheckboxInput" rel="nofollow"><code>CheckBoxInput</code></a> says "The value= HTML attribute by default is ‘y’ unless otherwise specified by value= at rendering."  I get an error whether I specify a value or not.  </p>
  
  <p>I can't seem to find an example of how to render a simple CheckBoxInput.  Any help is appreciated.</p>
  
  <p>Here's my form:</p>
  
  <pre><code>class PreferencesForm(Form):
      prefs = widgets.CheckboxInput()
  </code></pre>
  
  <p>Here's my template:</p>
  
  <pre><code>{% extends "base.html" %}
  
  {% block content %}
  
  &lt;form method="POST" action="/user/prefs/"&gt;
      &lt;div&gt;{{ form.prefs(value='n') }}&lt;/div&gt;
      &lt;button type="submit" class="btn"&gt;Submit&lt;/button&gt;    
  &lt;/form&gt;
  
  {% endblock %}
  </code></pre>