content: from django import forms
  from django.utils.translation import gettext_lazy as _
  
  __all__ = (
      'BaseVCMemberFormSet',
  )
  
  
  class BaseVCMemberFormSet(forms.BaseModelFormSet):
  
      def clean(self):
          super().clean()
  
          # Check for duplicate VC position values
          vc_position_list = []
          for form in self.forms:
              vc_position = form.cleaned_data.get('vc_position')
              if vc_position:
                  if vc_position in vc_position_list:
                      error_msg = _("A virtual chassis member already exists in position {vc_position}.").format(
                          vc_position=vc_position
                      )
                      form.add_error('vc_position', error_msg)
                  vc_position_list.append(vc_position)
  