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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def DeregisterFormatter(cls, formatter_class):
 """Deregisters a formatter class. The formatter classes are identified based on their lower case data type. Args: formatter_class (type):
 class of the formatter. Raises: KeyError: if formatter class is not set for the corresponding data type. """

    formatter_data_type = formatter_class.DATA_TYPE.lower()
    if formatter_data_type not in cls._formatter_classes:
      raise KeyError(
          'Formatter class not set for data type: {0:s}.'.format(
              formatter_class.DATA_TYPE))

    del cls._formatter_classes[formatter_data_type]