docs: def formfield_for_dbfield(self, db_field, **kwargs):
          """
          Hook for specifying the form Field instance for a given
          database Field instance. If kwargs are given, they're
          passed to the form Field's constructor.
  
          Default implementation uses the overrides returned by
          `get_formfield_overrides`. If a widget is an instance
          of APIChoiceWidget this will do lookup on the current
          admin site for the bundle that is registered for that
          module as the primary bundle for that one model. If a
          match is found then this will call update_links on that
          widget to store the appropriate urls for the javascript
          to call. Otherwise the widget is removed and the default
          select widget will be used instead.
          """
  
          overides = self.get_formfield_overrides()
  
          # If we've got overrides for the formfield defined, use 'em. **kwargs
          # passed to formfield_for_dbfield override the defaults.
          for klass in db_field.__class__.mro():
              if klass in overides:
                  kwargs = dict(overides[klass], **kwargs)
                  break
  
          # Our custom widgets need special init
          mbundle = None
          extra = kwargs.pop('widget_kwargs', {})
          widget = kwargs.get('widget')
          if kwargs.get('widget'):
              if widget and isinstance(widget, type) and \
                              issubclass(widget, widgets.APIChoiceWidget):
                  mbundle = self.bundle.admin_site.get_bundle_for_model(
                                                  db_field.rel.to)
                  if mbundle:
                      widget = widget(db_field.rel, **extra)
                  else:
                      widget = None
  
          if getattr(self, 'prepopulated_fields', None) and \
                          not getattr(self, 'object', None) and \
                          db_field.name in self.prepopulated_fields:
              extra = kwargs.pop('widget_kwargs', {})
              attr = extra.pop('attrs', {})
              attr['data-source-fields'] = self.prepopulated_fields[db_field.name]
              extra['attrs'] = attr
              if not widget:
                  from django.forms.widgets import TextInput
                  widget = TextInput(**extra)
              elif widget and isinstance(widget, type):
                  widget = widget(**extra)
  
          kwargs['widget'] = widget
  
          field = db_field.formfield(**kwargs)
          if mbundle:
              field.widget.update_links(self.request, self.bundle.admin_site)
          return field