code: function(parser, reporter) {
          "use strict";
          var rule = this,
              MAX_IMPORT_COUNT = 31,
              count = 0;
  
          function startPage() {
              count = 0;
          }
  
          parser.addListener("startpage", startPage);
  
          parser.addListener("import", function() {
              count++;
          });
  
          parser.addListener("endstylesheet", function() {
              if (count > MAX_IMPORT_COUNT) {
                  reporter.rollupError(
                      "Too many @import rules (" + count + "). IE6-9 supports up to 31 import per stylesheet.",
                      rule
                  );
              }
          });
      }
docs: initialization