title: Django how to override clean() method in a subclass of custom form?
body: <p>I created a custom form with custom validation like this:</p>
  
  <pre><code>class MyCustomForm(forms.Form):
      # ... form fields here
  
      def clean(self):
          cleaned_data = self.cleaned_data
          # ... do some cross-fields validation here
  
          return cleaned_data
  </code></pre>
  
  <p>Now, this form is subclassed with another form which has its own clean method.<br>
  What is the correct way to trigger both clean() methods?<br>
  At the moment, this is what I do:</p>
  
  <pre><code>class SubClassForm(MyCustomForm):
      # ... additional form fields here
  
      def clean(self):
          cleaned_data = self.cleaned_data
          # ... do some cross-fields validation for the subclass here
  
          # Then call the clean() method of the super  class
          super(SubClassForm, self).clean()
  
          # Finally, return the cleaned_data
          return cleaned_data
  </code></pre>
  
  <p>It seems to work. However, this makes two clean() methods return <code>cleaned_data</code> which seems to me a bit odd.<br>
  Is this the correct way?</p>