(PHP 5, PHP 7)
    Represents comment nodes, characters delimited by <!--
    and -->.
   
$exclusive
   [, bool $with_comments
   [, array $xpath
   [, array $ns_prefixes
  ]]]] )$uri
   [, bool $exclusive
   [, bool $with_comments
   [, array $xpath
   [, array $ns_prefixes
  ]]]] )