code: function mergeAxisOptionFromParallel(option) {
      var axes = modelUtil.normalizeToArray(option.parallelAxis);
  
      zrUtil.each(axes, function (axisOption) {
          if (!zrUtil.isObject(axisOption)) {
              return;
          }
  
          var parallelIndex = axisOption.parallelIndex || 0;
          var parallelOption = modelUtil.normalizeToArray(option.parallel)[parallelIndex];
  
          if (parallelOption && parallelOption.parallelAxisDefault) {
              zrUtil.merge(axisOption, parallelOption.parallelAxisDefault, false);
          }
      });
  }
docs: Merge aixs definition from parallel option (if exists) to axis option.
  @inner