Returns the best match for the given operator type from the list
        of choices.
        
        :param      operatorType | <Query.Op>
                    value        | <variant>
        
        :return     <str>

def operator(self, operatorType, value):
        """
        Returns the best match for the given operator type from the list
        of choices.
        
        :param      operatorType | <Query.Op>
                    value        | <variant>
        
        :return     <str>
        """
        if type(value) == datetime.timedelta:
            if operatorType == Query.Op.After:
                return 'after (delta)'
            elif operatorType == Query.Op.Before:
                return 'before (delta)'
        
        return super(DateTimePlugin, self).operator(operatorType, value)