None and stale references

Questions 1 to 5 of 6

1. 1. The program below crashes. Which line causes the crash, and why? ``python stock = {'apple': 4} count = stock.get('pear') print(count + 1) ``

   stock.get('pear') raises a KeyError, so the crash is on the get lineprint cannot show a number that comes from a dictionarystock.get('pear') returns None because the key is missing, and None + 1 raises a TypeError on the print lineA dictionary literal cannot hold a string key, so stock is empty
2. 2. The code below calls a method on a value that may be None. Which change makes the check safe? ``python name = None if name.lower() == 'ana': print('hi Ana') ``

   Write name.strip() == 'ana', because strip returns an empty string for NoneWrite len(name) == 3, because len returns 0 for NoneWrite name.upper() == 'ANA', because upper-case text never crashesWrite name == 'ana', because == never calls a method on name
3. 3. A crash prints this message: AttributeError: 'NoneType' object has no attribute 'upper'. What does the message tell you?

   The text is too long for upper to handle, so Python stopped the programThe value used was None, and None has no method called upperThe string module is missing from this Python installupper was called with the wrong number of arguments
4. 4. What does this check do when name is None? ``python def label(name): if name is None: raise ValueError('name must not be None') return 'Item: ' + name ``

   It raises a ValueError with your message, so the error points at the bad value where it arrivedIt returns an empty string so that the rest of the function can runIt prints the message and returns None to the callerIt returns False and skips the rest of the function without an error
5. 5. What does this program print? ``python text = None print(text or '(missing)') name = None print('empty' if name is None else name.strip()) try: print(text.upper()) except AttributeError: print('caught') ``

   (missing) empty then a traceback, because the except misses this error(missing) ready caught(missing) empty caughtNone None None