text: from django import forms
  from django.forms.utils import ErrorList
  
  class FormUserNeededMixin(object):
  
       def form_valid(self, form):
          if self.request.user.is_authenticated:
              form.instance.user = self.request.user
              return super(FormUserNeededMixin,self).form_valid(form)
          else:
              form._errors[forms.forms.NON_FIELD_ERRORS] = ErrorList(["User must be logged in to continue."])
              return self.form_invalid(form)
  
  class UserOwnerMixin(object):
      def form_valid(self, form):
              if form.instance.user == self.request.user:
                  return super(UserOwnerMixin, self).form_valid(form)
              else:
                  form._errors[forms.forms.NON_FIELD_ERRORS] = ErrorList(["This user is not allowed to change this data. Must be logged in!"])
                  return self.form_invalid(form)
  
  