def save_model(self, request, obj, form, change):
    if (not change):
        site_list = self.get_site_list(request)
        if (len(site_list) == 1):
            obj.site = site_list.get()
    return super(MultiSiteCalloutAdmin, self).save_model(request, obj, form, change)
def save_model(self, request, obj, form, change):
    if (not change):
        site_list = self.get_site_list(request)
        if (len(site_list) == 1):
            obj.site = site_list.get()
    return super(MultiSiteCalloutAdmin, self).save_model(request, obj, form, change)