code: def authorize_dbsecurity_group(self, group_name, cidr_ip=None,
                                     ec2_security_group_name=None,
                                     ec2_security_group_owner_id=None):
          
          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)
docs: 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.