input: Write a function to sort a dictionary according to its values in descending order.
  def sortDictionary(dictionary):
    sorted_list = sorted(dictionary.items(), key=lambda x: x[1], reverse=True)
    sorted_dictionary = dict(sorted_list)
    return sorted_dictionary
  assert sortDictionary({'apple': 2, 'banana': 3, 'mango': 1})=={'banana': 3, 'apple': 2, 'mango': 1}
  assert sortDictionary({'car': 10, 'bike': 5, 'truck': 20})=={'truck': 20, 'car': 10, 'bike': 5}
  assert sortDictionary({})=={}
  assert sortDictionary({'a': 1, 'b': 1, 'c': 2})=={'c': 2, 'a': 1, 'b': 1}
output: def sortDictionary(dictionary):
    sorted_list = sorted(dictionary.items(), key=lambda x: x[1], reverse=True)
    sorted_dictionary = dict(sorted_list)
    return sorted_dictionary