def _in_valid_interval(self, parameter, value):
        """Returns if the parameter is within its valid interval.

        :param string parameter:     Name of the parameter that has to be checked.
        :param numeric value:     Value of the parameter.

        :return:    Returns :py:const:`True` it the value for the given parameter is valid,
            :py:const:`False` otherwise.
        :rtype: boolean
        """
        # return True, if not interval is defined for the parameter
        if parameter not in self._parameterIntervals:
            return True

        interval = self._parameterIntervals[parameter]

        if interval[2] and interval[3]:
            return interval[0] <= value <= interval[1]

        if not interval[2] and interval[3]:
            return interval[0] <  value <= interval[1]

        if interval[2] and not interval[3]:
            return interval[0] <= value <  interval[1]

        #if False == interval[2] and False == interval[3]:
        return interval[0] < value < interval[1]