docs: def is_using_format(cls, markers, used_formats=None):
          """
          Args:
              markers (str | unicode): Space separated list of markers to look for
              used_formats (str | unicode): Formats to consider (default: cls.used_formats)
  
          Returns:
              (bool): True if any one of the 'markers' is seen in 'used_formats'
          """
          if used_formats is None:
              used_formats = cls.used_formats
          if not markers or not used_formats:
              return False
          return any(marker in used_formats for marker in flattened(markers, split=(" ", UNIQUE)))