def render(fmt = :sass)
      check_encoding!
      build_tree.send("to_#{fmt}", @options).strip + "\n"
    rescue Sass::SyntaxError => err
      err.modify_backtrace(:filename => @options[:filename] || '(css)')
      raise err
    end
def render(fmt = :sass)
      check_encoding!
      build_tree.send("to_#{fmt}", @options).strip + "\n"
    rescue Sass::SyntaxError => err
      err.modify_backtrace(:filename => @options[:filename] || '(css)')
      raise err
    end
@param template [String] The CSS stylesheet.
   This stylesheet can be encoded using any encoding
   that can be converted to Unicode.
   If the stylesheet contains an `@charset` declaration,
   that overrides the Ruby encoding
   (see {file:SASS_REFERENCE.md#Encodings the encoding documentation})
 @option options :old [Boolean] (false)
     Whether or not to output old property syntax
     (`:color blue` as opposed to `color: blue`).
     This is only meaningful when generating Sass code,
     rather than SCSS.
 @option options :indent [String] ("  ")
     The string to use for indenting each line. Defaults to two spaces.
 Converts the CSS template into Sass or SCSS code.

 @param fmt [Symbol] `:sass` or `:scss`, designating the format to return.
 @return [String] The resulting Sass or SCSS code
 @raise [Sass::SyntaxError] if there's an error parsing the CSS template