code: def save(self, commit=True):
          
          saved_obj = self.save_form(commit=commit)
          self.save_forms(commit=commit)
          self.save_formsets(commit=commit)
          return saved_obj
docs: When saving a super model form, the nested forms and formsets will be
          saved as well.
  
          The implementation of ``.save()`` looks like this:
  
          .. code:: python
  
              saved_obj = self.save_form()
              self.save_forms()
              self.save_formsets()
              return saved_obj
  
          That makes it easy to override it in order to change the order in which
          things are saved.
  
          The ``.save()`` method will return only a single model instance even if
          nested forms are saved as well. That keeps the API similiar to what
          Django's model forms are offering.
  
          If ``commit=False`` django's modelform implementation will attach a
          ``save_m2m`` method to the form instance, so that you can call it
          manually later. When you call ``save_m2m``, the ``save_forms`` and
          ``save_formsets`` methods will be executed as well so again all nested
          forms are taken care of transparantly.