input: Write a python function to match dictionary keys and return a new dictionary with keys that exist in both dictionaries and their corresponding values as tuples.
  assert match_dict_keys({'a': 1, 'b': 2, 'c': 3}, {'b': 20, 'c': 30, 'd': 40}) == {'b': (2, 20), 'c': (3, 30)}
  assert match_dict_keys({'x': 9, 'y': 8}, {'y': 80, 'z': 70}) == {'y': (8, 80)}
  assert match_dict_keys({'p': 10}, {'q': 20}) == {}
output: def match_dict_keys(dict1, dict2):
      return {k: (dict1[k], dict2[k]) for k in dict1 if k in dict2}