Making word Bold with Python script

Hi all,

If I have this script:

def Test():
  if SendMail("[email protected]", "mail.johnsmithcorp.com", "John Smith", "[email protected]", "Notification", "Hello Clare, Your application is nice.", "C:\\File1.txt", "C:\\File2.txt"):
    Log.Message("Mail was sent")
  else:
    Log.Warning("Mail was not sent")

How can I just make "Notification" Bold?