if elongation_negative_factors.get(rna_elongation_negative_factors[rna_kb.id]):
                for factor in elongation_negative_factors[rna_elongation_negative_factors[rna_kb.id]]:
                    factor_details = elongation_negative_factor_functions[
                        rna_elongation_negative_factors[rna_kb.id]][','.join(factor)]
                    expression_terms.append(factor_details['function'].id)