Bestätigungsabfrage

def ask_proceed(question, default="yes"):
    valid = {"yes":"yes", "y":"yes", "no":"no", "n":"no"}
    if default == None:
      prompt = " [y/n] "
    elif default == "yes":
      prompt = " [Y/n] "
    elif default == "no":
      prompt = " [y/N] "
    else:
      raise ValueError("invalid default answer: '%s'" % default)
 
    while 1:
      print (question + prompt)
      choice = raw_input().lower()
      if default is not None and choice == '':
        return default
      elif choice in valid.keys():
        return valid[choice]
      else:
        print ("Please respond with 'yes' or 'no' (or 'y' or 'n').\n")
 
 
result = ask_proceed("Do you want to continue?")
if result == "yes":
  print "A good choise! I will continue with whatever I was doing..."
if result == "no":
  print "Ok, bye!"