input: Write a python function to reverse the keys and values in a dictionary.
  assert reverse_dictionary({'a': 1, 'b': 2, 'c': 3}) == {1: 'a', 2: 'b', 3: 'c'}
  assert reverse_dictionary({'x': 10, 'y': 20, 'z': 30}) == {10: 'x', 20: 'y', 30: 'z'}
  assert reverse_dictionary({1: 'one', 2: 'two', 3: 'three'}) == {'one': 1, 'two': 2, 'three': 3}
output: def reverse_dictionary(d):
      return {v: k for k, v in d.items()}