    # File lib/rubygems/source_index.rb, line 119
      def load_gems_in(*spec_dirs)
        @gems.clear

        spec_dirs.reverse_each do |spec_dir|
          spec_files = Dir.glob File.join(spec_dir, '*.gemspec')

          spec_files.each do |spec_file|
            gemspec = self.class.load_specification spec_file.untaint
            add_spec gemspec if gemspec
          end
        end

        self
      end