open (Gem::Package)

    # File lib/rubygems/package.rb, line 782
      def self.open(dest, mode = "r", signer = nil, &block)
        raise "Block needed" unless block_given?

        case mode
        when "r"
          security_policy = signer
          TarInput.open(dest, security_policy, &block)
        when "w"
          TarOutput.open(dest, signer, &block)
        else
          raise "Unknown Package open mode"
        end
      end