def parse_selectors(root)
      root.children.each do |child|
        next parse_selectors(child) if child.is_a?(Tree::DirectiveNode)
        next unless child.is_a?(Tree::RuleNode)
        parser = Sass::SCSS::CssParser.new(child.rule.first, child.filename, nil, child.line)
        child.parsed_rules = parser.parse_selector
      end
    end
def parse_selectors(root)
      root.children.each do |child|
        next parse_selectors(child) if child.is_a?(Tree::DirectiveNode)
        next unless child.is_a?(Tree::RuleNode)
        parser = Sass::SCSS::CssParser.new(child.rule.first, child.filename, nil, child.line)
        child.parsed_rules = parser.parse_selector
      end
    end
Parse all the selectors in the document and assign them to
 {Sass::Tree::RuleNode#parsed_rules}.

 @param root [Tree::Node] The parent node