docs: function (steps) {
              var scenarioArrowCollection = document.querySelectorAll('.scenario-arrow'),
                  allBtn = document.querySelector('.all-btn');
              for (var i = 0; i < steps.length; i++) {
                  var display = steps[i].style.display;
                  if (display === 'none' || display === '') {
                      this.addArrowUp(scenarioArrowCollection);
                      steps[i].style.display = 'block';
                      allBtn.classList.add('active');
                  } else {
                      this.addArrowDown(scenarioArrowCollection);
                      allBtn.classList.add('active');
                      steps[i].style.display = 'none';
                  }
              }
          }