def is_duplicated(form, field): """Check if the given facet is already assigned to this collection. :param form: the form containing the validated field :param field: the validated field """ facet_name = field.data collection = form.data['collection'] if not collection: return if FacetCollection.is_duplicated(collection.id, facet_name): raise ValidationError( 'This facet is already assigned to this collection.')