title: overwrite form for django CreateView
body: <p>Perhaps just another stupid beginner question:
  I am having trouble overwriting a django model form which is currently using the following code in views.py.</p>
  
  <p>The code below works well !</p>
  
  <pre><code>class PostCreateView(LoginRequiredMixin, CreateView):
      model = Post
      fields = ['title', 'content']
  
      ### want this instead of line 1 and 2 above --&gt; form_class = PostCreateForm()
  
      view_args = collections.namedtuple('view_args', ['page_title'])
      view_args = view_args(page_title="Create Post")
  
      def get_context_data(self, *args, **kwargs):
          self.tgt_url_args = MyHelper.parse_tgt_url(self)
          context = super(PostCreateView, self).get_context_data(*args, **kwargs)
          context.update(MyHelper.get_context_metadata(self, self.tgt_url_args, PostCreateView.view_args))
          return context
  
      def form_valid(self, form):
          form.instance.author = self.request.user
          tgt_url_args = MyHelper.parse_tgt_url(self)
          blog_article = Article.objects.get(pk=tgt_url_args.get('Article', '0'))
          form.instance.article_field = blog_article
          return super().form_valid(form)
  </code></pre>
  
  <p>However, I would like to overwrite the form in order to add placeholder to the fields. So I replace line 1 and 2 by:</p>
  
  <pre><code>form_class = PostCreateForm()
  </code></pre>
  
  <p>I also added the follwing in forms.py:</p>
  
  <pre><code>from django import forms
  from . models import Post
  
  
  class PostCreateForm(forms.ModelForm):
  
  
      class Meta:
          model = Post
          fields = ['title', 'content']
  
  print('imported PostCreateForm')
  </code></pre>
  
  <p>When I import and run this however, I get the following error:</p>
  
  <pre><code>'PostCreateForm' object is not callable
  </code></pre>
  
  <p>What am I doing wrong here?</p>