code: def get_random_word(dictionary, starting_letter=None):
      
      if starting_letter is None:
          starting_letter = random.choice(list(dictionary.keys()))
  
      try:
          to_return = random.choice(dictionary[starting_letter])
      except KeyError:
          msg = "Dictionary does not contain a word starting with '{}'"
          raise NoWordForLetter(msg.format(starting_letter))
  
      return to_return
docs: Takes the dictionary to read from and returns a random word
      optionally accepts a starting letter