input: Write a python function to reverse the keys and values in a dictionary.
  assert reverse_dict({"one": "apple", "two": "banana", "three": "pear"}) == {'apple': 'one', 'banana': 'two', 'pear': 'three'}
  assert reverse_dict({"a": 1, "b": 2, "c": 3}) == {1: 'a', 2: 'b', 3: 'c'}
  assert reverse_dict({"x": "red", "y": "green", "z": "blue"}) == {'red': 'x', 'green': 'y', 'blue': 'z'}
output: def reverse_dict(d):
      return {v: k for k, v in d.items()}