code: function _getSelectorInFinalCSSForm(selectorArray) {
          var finalSelectorArray = [""],
              parentSelectorArray = [],
              group = [];
          _.forEach(selectorArray, function (selector) {
              selector = _stripAtRules(selector);
              group = selector.split(",");
              parentSelectorArray = [];
              _.forEach(group, function (cs) {
                  var ampersandIndex = cs.indexOf("&");
                  _.forEach(finalSelectorArray, function (ps) {
                      if (ampersandIndex === -1) {
                          cs = _stripAtRules(cs);
                          if (ps.length && cs.length) {
                              ps += " ";
                          }
                          ps += cs;
                      } else {
                          // Replace all instances of & with regexp
                          ps = _stripAtRules(cs.replace(/&/g, ps));
                      }
                      parentSelectorArray.push(ps);
                  });
              });
              finalSelectorArray = parentSelectorArray;
          });
          return finalSelectorArray.join(", ");
      }
docs: Converts the given selector array into the actual CSS selectors similar to
  those generated by a CSS preprocessor.
  
  @param {Array.<string>} selectorArray
  @return {string}