input: Write a function to sort a dictionary according to its values in descending order. If the dictionary is empty, return an empty dictionary.
  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({'dog': 5, 'cat': 1, 'fish': 7})=={'fish': 7, 'dog': 5, 'cat': 1}
  assert sortDictionary({})=={}
  assert sortDictionary({'zero': 0})=={'zero': 0}
output: def sortDictionary(dictionary):
    sorted_list = sorted(dictionary.items(), key=lambda x: x[1], reverse=True)
    sorted_dictionary = dict(sorted_list)
    return sorted_dictionary