@classmethod
def RegisterFormatters(cls, formatter_classes):
    """Registers formatter classes.

    The formatter classes are identified based on their lower case data type.

    Args:
      formatter_classes (list[type]): classes of the formatters.

    Raises:
      KeyError: if formatter class is already set for the corresponding
          data type.
    """
    for formatter_class in formatter_classes:
        cls.RegisterFormatter(formatter_class)
