def data
      unless @data
        @data = {}
        @path.find do |descendant|
          if Puppet::ModuleTool.artifact?(descendant)
            Find.prune
          elsif descendant.file?
            path = descendant.relative_path_from(@path)
            @data[path.to_s] = checksum(descendant)
          end
        end
      end
      return @data
    end
def data
      unless @data
        @data = {}
        @path.find do |descendant|
          if Puppet::ModuleTool.artifact?(descendant)
            Find.prune
          elsif descendant.file?
            path = descendant.relative_path_from(@path)
            @data[path.to_s] = checksum(descendant)
          end
        end
      end
      return @data
    end
Return checksums for object's +Pathname+, generate if it's needed.
 Result is a hash of path strings to checksum strings.