How to use the pyulog.core.ULog.MessageFormat function in pyulog

header = self._MessageHeader()
        while True:
            data = self._file_handle.read(3)
            if not data:
                break
            header.initialize(data)
            data = self._file_handle.read(header.msg_size)
            try:
                if header.msg_type == self.MSG_TYPE_INFO:
                    msg_info = self._MessageInfo(data, header)
                    self._msg_info_dict[msg_info.key] = msg_info.value
                elif header.msg_type == self.MSG_TYPE_INFO_MULTIPLE:
                    msg_info = self._MessageInfo(data, header, is_info_multiple=True)
                    self._add_message_info_multiple(msg_info)
                elif header.msg_type == self.MSG_TYPE_FORMAT:
                    msg_format = self.MessageFormat(data, header)
                    self._message_formats[msg_format.name] = msg_format
                elif header.msg_type == self.MSG_TYPE_PARAMETER:
                    msg_info = self._MessageInfo(data, header)
                    self._initial_parameters[msg_info.key] = msg_info.value
                elif (header.msg_type == self.MSG_TYPE_ADD_LOGGED_MSG or
                      header.msg_type == self.MSG_TYPE_LOGGING or
                      header.msg_type == self.MSG_TYPE_LOGGING_TAGGED):
                    self._file_handle.seek(-(3+header.msg_size), 1)
                    break # end of section
                elif header.msg_type == self.MSG_TYPE_FLAG_BITS:
                    # make sure this is the first message in the log
                    if self._file_handle.tell() != 16 + 3 + header.msg_size:
                        print('Error: FLAGS_BITS message must be first message. Offset:',
                              self._file_handle.tell())
                    msg_flag_bits = self._MessageFlagBits(data, header)
                    self._compat_flags = msg_flag_bits.compat_flags