def __refillOTPKs(self):
        """
        If the amount of available OTPKs fell under the minimum, refills the OTPKs up to
        the maximum limit again.
        """

        remainingOTPKs = len(self.__otpks)

        if remainingOTPKs < self.__min_num_otpks:
            self.__generateOTPKs(self.__max_num_otpks - remainingOTPKs)