original_string: protected static function getInstance()
      {
          $class = get_called_class();
  
          if (!isset(self::$instance[$class]) || !self::$instance[$class] instanceof $class) {
              self::$instance[$class] = new static();
          }
  
          return static::$instance[$class];
      }
code: protected static function getInstance()
      {
          $class = get_called_class();
  
          if (!isset(self::$instance[$class]) || !self::$instance[$class] instanceof $class) {
              self::$instance[$class] = new static();
          }
  
          return static::$instance[$class];
      }
code_tokens: protected static function getInstance ( ) { $ class = get_called_class ( ) ; if ( ! isset ( self :: $ instance [ $ class ] ) || ! self :: $ instance [ $ class ] instanceof $ class ) { self :: $ instance [ $ class ] = new static ( ) ; } return static :: $ instance [ $ class ] ; }
docstring: Returns the singleton instance.
  
  @return self
docstring_tokens: Returns the singleton instance .