original_string: public static function get($key = null)
      {
          if (null === self::$instance) {
              self::$instance = new self();
          }
  
          return $key ? self::$instance[$key] : self::$instance;
      }
code: public static function get($key = null)
      {
          if (null === self::$instance) {
              self::$instance = new self();
          }
  
          return $key ? self::$instance[$key] : self::$instance;
      }
code_tokens: public static function get ( $ key = null ) { if ( null === self :: $ instance ) { self :: $ instance = new self ( ) ; } return $ key ? self :: $ instance [ $ key ] : self :: $ instance ; }
docstring: Returns the application singleton.
  
  @param string $key A service or parameter key.
  
  @return Go The application singleton.
docstring_tokens: Returns the application singleton .