# File lib/active_support/vendor/builder/xmlmarkup.rb, line 237
    def instruct!(directive_tag=:xml, attrs={})
      _ensure_no_block block_given?
      if directive_tag == :xml
        a = { :version=>"1.0", :encoding=>"UTF-8" }
        attrs = a.merge attrs
      end
      _special(
        "<?#{directive_tag}",
        "?>",
        nil,
        attrs,
        [:version, :encoding, :standalone])
    end