# File lib/fog/compute/openstack/models/security_group_rule.rb, line 16
        def save
          requires :ip_protocol, :from_port, :to_port, :parent_group_id
          cidr = ip_range && ip_range["cidr"]
          if rule = service.create_security_group_rule(parent_group_id, ip_protocol, from_port, to_port, cidr, group).data[:body]
            merge_attributes(rule["security_group_rule"])
          end
        end