Error when number of master nodes or worker nodes less than 3

The prepare.sh script runs smoothly when there're 3 master nodes and 3 worker nodes at least. However,If I list one master, one worker node as following in the inventory file:

[masters]
10.11.8.252 host="master-1" mac="00:00:0a:0b:08:c3"

[workers]
10.11.8.253 host="worker-1" mac="00:00:0a:0b:08:f0"

I got following error in the step generating dnsmasq.conf :

TASK [Generate dnsmasq.conf file] *************************************************************************************************************************************************************
Tuesday 25 October 2022  00:00:45 -0700 (0:00:00.301)       0:01:19.492 ******* 
An exception occurred during task execution. To see the full traceback, use -vvv. The error was: ansible.errors.AnsibleUndefinedVariable: list object has no element 1
fatal: [localhost]: FAILED! => changed=false 
  msg: 'AnsibleUndefinedVariable: list object has no element 1'

IBM-ICP4D / cloud-pak-ocp-4

Error when number of master nodes or worker nodes less than 3 #35