issue regarding testing modbus_server_test.py

[Mdmorshadurrahman]

while running the command "rosrun niryo_one_modbus modbus_server_test.py" to run the server

got this error:

Traceback (most recent call last):
File "/home/joseph/Niryo_ws/src/niryo_one_ros/niryo_one_modbus/examples/modbus_server_test.py", line 9, in
server = ModbusServer("0.0.0.0", 5020)
File "/home/joseph/Niryo_ws/src/niryo_one_ros/niryo_one_modbus/src/niryo_one_modbus/modbus_server.py", line 40, in init
self.holding_register = HoldingRegisterDataBlock()
File "/home/joseph/Niryo_ws/src/niryo_one_ros/niryo_one_modbus/src/niryo_one_modbus/holding_register_data_block.py", line 104, in init
self.tool_command_list = rospy.get_param("/niryo_one_tools/command_list")
File "/opt/ros/noetic/lib/python3/dist-packages/rospy/client.py", line 467, in get_param
return _param_server[param_name] #MasterProxy does all the magic for us
File "/opt/ros/noetic/lib/python3/dist-packages/rospy/msproxy.py", line 123, in getitem
raise KeyError(key)
KeyError: '/niryo_one_tools/command_list'

looking for help to solve this issue so badly :(