Add a new rule to an existing security group.
        You need to pass in either src_security_group_name and
        src_security_group_owner_id OR a CIDR block but not both.

        :type group_name: string
        :param group_name: The name of the security group you are adding
                           the rule to.

        :type ec2_security_group_name: string
        :param ec2_security_group_name: The name of the EC2 security group
                                        you are granting access to.

        :type ec2_security_group_owner_id: string
        :param ec2_security_group_owner_id: The ID of the owner of the EC2
                                            security group you are granting
                                            access to.

        :type cidr_ip: string
        :param cidr_ip: The CIDR block you are providing access to.
                        See http://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing

        :rtype: bool
        :return: True if successful.

def authorize_dbsecurity_group(self, group_name, cidr_ip=None,
                                   ec2_security_group_name=None,
                                   ec2_security_group_owner_id=None):
        """
        Add a new rule to an existing security group.
        You need to pass in either src_security_group_name and
        src_security_group_owner_id OR a CIDR block but not both.

        :type group_name: string
        :param group_name: The name of the security group you are adding
                           the rule to.

        :type ec2_security_group_name: string
        :param ec2_security_group_name: The name of the EC2 security group
                                        you are granting access to.

        :type ec2_security_group_owner_id: string
        :param ec2_security_group_owner_id: The ID of the owner of the EC2
                                            security group you are granting
                                            access to.

        :type cidr_ip: string
        :param cidr_ip: The CIDR block you are providing access to.
                        See http://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing

        :rtype: bool
        :return: True if successful.
        """
        params = {'DBSecurityGroupName':group_name}
        if ec2_security_group_name:
            params['EC2SecurityGroupName'] = ec2_security_group_name
        if ec2_security_group_owner_id:
            params['EC2SecurityGroupOwnerId'] = ec2_security_group_owner_id
        if cidr_ip:
            params['CIDRIP'] = urllib.quote(cidr_ip)
        return self.get_object('AuthorizeDBSecurityGroupIngress', params,
                               DBSecurityGroup)