def update_stylesheets(individual_files = [])
      Sass::Plugin.checked_for_updates = true
      staleness_checker = StalenessChecker.new(engine_options)

      files = file_list(individual_files)
      run_updating_stylesheets(files)

      updated_stylesheets = []
      files.each do |file, css, sourcemap|
        # TODO: Does staleness_checker need to check the sourcemap file as well?
        if options[:always_update] || staleness_checker.stylesheet_needs_update?(css, file)
          # XXX For consistency, this should return the sourcemap too, but it would
          # XXX be an API change.
          updated_stylesheets << [file, css]
          update_stylesheet(file, css, sourcemap)
        else
          run_not_updating_stylesheet(file, css, sourcemap)
        end
      end
      run_updated_stylesheets(updated_stylesheets)
    end
def update_stylesheets(individual_files = [])
      Sass::Plugin.checked_for_updates = true
      staleness_checker = StalenessChecker.new(engine_options)

      files = file_list(individual_files)
      run_updating_stylesheets(files)

      updated_stylesheets = []
      files.each do |file, css, sourcemap|
        # TODO: Does staleness_checker need to check the sourcemap file as well?
        if options[:always_update] || staleness_checker.stylesheet_needs_update?(css, file)
          # XXX For consistency, this should return the sourcemap too, but it would
          # XXX be an API change.
          updated_stylesheets << [file, css]
          update_stylesheet(file, css, sourcemap)
        else
          run_not_updating_stylesheet(file, css, sourcemap)
        end
      end
      run_updated_stylesheets(updated_stylesheets)
    end
Updates out-of-date stylesheets.

 Checks each Sass/SCSS file in
 {file:SASS_REFERENCE.md#template_location-option `:template_location`}
 to see if it's been modified more recently than the corresponding CSS file
 in {file:SASS_REFERENCE.md#css_location-option `:css_location`}.
 If it has, it updates the CSS file.

 @param individual_files [Array<(String, String[, String])>]
   A list of files to check for updates
   **in addition to those specified by the
   {file:SASS_REFERENCE.md#template_location-option `:template_location` option}.**
   The first string in each pair is the location of the Sass/SCSS file,
   the second is the location of the CSS file that it should be compiled to.
   The third string, if provided, is the location of the Sourcemap file.