code: def _validate_master(new_class):
      
      if not new_class.master or not isinstance(new_class.master, ForwardManyToOneDescriptor):
          raise ImproperlyConfigured("{0}.master should be a ForeignKey to the shared table.".format(new_class.__name__))
  
      remote_field = new_class.master.field.remote_field
      shared_model = remote_field.model
  
      meta = shared_model._parler_meta
      if meta is not None:
          if meta._has_translations_model(new_class):
              raise ImproperlyConfigured("The model '{0}' already has an associated translation table!".format(shared_model.__name__))
          if meta._has_translations_field(remote_field.related_name):
              raise ImproperlyConfigured("The model '{0}' already has an associated translation field named '{1}'!".format(shared_model.__name__, remote_field.related_name))
  
      return shared_model
docs: Check whether the 'master' field on a TranslatedFieldsModel is correctly configured.