Unable to initial WPT Agent

[sai kiran]

Traceback (most recent call last):
File "C:\wpt_agent_sep2018\wptagent\wptagent.py", line 705, in <module>
main()
File "C:\wpt_agent_sep2018\wptagent\wptagent.py", line 692, in main
browsers = find_browsers()
File "C:\wpt_agent_sep2018\wptagent\wptagent.py", line 465, in find_browsers
build = get_windows_build()
File "C:\wpt_agent_sep2018\wptagent\wptagent.py", line 395, in get_windows_build
return int(output.strip().split(' ')[-1])
ValueError: invalid literal for int() with base 10: ''