WTForm GAE model_field doesn't render fields in Jinja2 template
===

I get get my form to display using the WTForm model_form on Google App Engine.  I expect to see the fields displayed when I visit /admin/newpost

**My Model**

    class BlogPost(db.Model):
        #The URL path to the blog post. Posts have a path if they are published.
        path = db.StringProperty()
        title = db.StringProperty(required=True, indexed=False)
        body = db.TextProperty(required=True)
        published = db.DateTimeProperty(auto_now_add=True)
        updated = db.DateTimeProperty(auto_now=True)

**My PostHandler**

    class PostHandler(webapp2.RequestHandler):
    
    @webapp2.cached_property
    def jinja2(self):
        return jinja2.get_jinja2(app=self.app)

    def render_to_response(
        self,
        template_name,
        template_vals=None,
        theme=None
        ):
        template_name = "admin/%s" % template_name
        self.response.out.write(render_template(
            template_name, template_vals, theme))

    def render_form(self, form):
        self.render_to_response("edit.html", {'form': form()})

    def get(self):
        form = model_form(BlogPost)
        self.render_form(form)


**Edit.html Template That Does Not Work**

    {% extends "base.html" %}
    {% block title %}New Post{% endblock %}
    {% block body %}
      <form method="post" action="">
        <table>
          {{form}}
        </table>
        <input type="submit" />
      </form>
    {% endblock %}

With this template I see html with a form button.  The problem is none of the model fields get displayed.  To get my fields to display I have to do this...

**Edit.html Template That Works**


    {% extends "base.html" %}
    {% block title %}Testing New Post Template{% endblock %}
    {% block body %}
      <form method="post" action="">
        <table>
    
    <div>{{ form.title.label }}: {{ form.title(class="css_class") }}</div>
    {% if form.title.errors %}
            <ul class="errors">{% for error in form.name.errors %}<li>{{ error }}</li>{% endfor %}</ul>
        {% endif %}
    
    <div>{{ form.body.label }}: {{ form.body() }}</div>
    {% if form.body.errors %}
            <ul class="errors">{% for error in form.body.errors %}<li>{{ error }}</li>{% endfor %}</ul>
        {% endif %}
    
        </table>
        <input type="submit" />
      </form>
    {% endblock %}

In short, how to I get the first version to display my model fields in the form?