input: Write a function to sort a dictionary according to its values in descending order. The function should take a dictionary as input and return a new dictionary with the same keys but sorted by their values.
  assert sortDictionary({'apple': 2, 'banana': 3, 'mango': 1})=={'banana': 3, 'apple': 2, 'mango': 1}
  assert sortDictionary({'car': 5, 'bike': 4, 'scooter': 6})=={'scooter': 6, 'car': 5, 'bike': 4}
  assert sortDictionary({'x': 10, 'y': 10, 'z': 1})=={'x': 10, 'y': 10, 'z': 1}
  assert sortDictionary({'a': 0, 'b': -1, 'c': 0})=={'a': 0, 'c': 0, 'b': -1}
  assert sortDictionary({})=={}
output: def sortDictionary(d):
      return {k: v for k, v in sorted(d.items(), key=lambda item: item[1], reverse=True)}