If statement for applications for windows, linux and Mac

crossPlatform.py

if sys.platform.startswith('win'):
    #Code for windows based
elif sys.platform.startswith('linux') or sys.platform.startswith('cygwin'):
    #Code for linux based systems
elif sys.platform.startswith('darwin'):
    #code for Mac Machines
else:
    raise EnvironmentError('Unsupported platform')