You can use below script to get any registry key value,
Note: This script will provide you architecture value of system
import _winreg;
key = getattr(_winreg,"HKEY_LOCAL_MACHINE")
handle = _winreg.OpenKey(key, "SYSTEM\CurrentControlSet\Control\Session Manager\Environment" )
(value, type) = _winreg.QueryValueEx(handle,"PROCESSOR_ARCHITECTURE")
print (value)
sample output would be,
