input: Write a function in Python to sort a dictionary according to its values, in descending order. The function should take a dictionary as input and return a new sorted dictionary. If the input dictionary is empty, the function should return an empty dictionary.
  assert sortDictionary({'apple': 2, 'banana': 3, 'mango': 1})=={'banana': 3, 'apple': 2, 'mango': 1}
  assert sortDictionary({})=={}
  assert sortDictionary({'a': 10, 'b': 5, 'c': 20})=={'c': 20, 'a': 10, 'b': 5}
output: def sortDictionary(d):
      return {k: v for k, v in sorted(d.items(), key=lambda item: item[1], reverse=True)}