    # File lib/chef/provider/package/yum.rb, line 510
              def initialize
                # package name => [ RPMPackage, RPMPackage ] of different versions
                @rpms = Hash.new
                # package nevra => RPMPackage for lookups
                @index = Hash.new
                # provide name (aka feature) => [RPMPackage, RPMPackage] each providing this feature
                @provides = Hash.new
                # RPMPackages listed as available
                @available = Set.new
                # RPMPackages listed as installed
                @installed = Set.new
              end