fix handling of win wmic source on error

* Update __init__.py for None result

* Rename variable and added additional check

Protects against any return that is too short which would lead to an IndexError

Author: MarkGooding

machineid/__init__.py

@@ -89,8 +89,10 @@ def id(winregistry: bool = True) -> str:
     if not id:
       id = __exec__("powershell.exe -ExecutionPolicy bypass -command (Get-CimInstance -Class Win32_ComputerSystemProduct).UUID")
     if not id:
-      id = __exec__('wmic csproduct get uuid').split('\n')[2] \
-                                              .strip()
+      out = __exec__('wmic csproduct get uuid')
+      if out is not None and out.count('\n')>1:
+          id = out.split('\n')[2].strip()
+          
   elif platform.startswith('linux'):
     id = __read__('/var/lib/dbus/machine-id')
     if not id: