code: def add_header_name(self, header_name, is_indexed=False):
          
          header = ConfigHeader()
          header.is_indexed = is_indexed
          self.headers[header_name] = header
          return header
docs: Adds a new header with the name header_name
          :param header_name: The name of the header as it would appear in the config
          :param is_indexed: Indicates that the header may contain special 'indexed' attributes, where a series of
          keys that differ only by a numeric suffix are used to represent an array. Example:
          thing_1 = x
          thing_2 = y
          :return: The newly created header.