def exists?(filename)
      if File.exists?(@path)
        File.exists?(path_to(filename))
      else
        Zip::ZipFile::foreach(@package) do |entry|
          return true if entry.name == filename
        end
        false
      end
    end
def exists?(filename)
      if File.exists?(@path)
        File.exists?(path_to(filename))
      else
        Zip::ZipFile::foreach(@package) do |entry|
          return true if entry.name == filename
        end
        false
      end
    end
Returns +true+ if the specified file (or directory) exists in the package.