Python os module
Specifically for Python 3.6/3.7:
os.name: The name of the operating
system dependent module imported. The
following names have currently been
registered: 'posix', 'nt', 'java'.
In your case, you want to check for 'nt' as os.name output:
import os
if os.name == 'nt':
...
There is also a note on os.name:
See also sys.platform has a finer granularity. os.uname() gives
system-dependent version information.
The platform module provides
detailed checks for the system’s identity.