input: Write a python function to find the maximum value in a dictionary.
  assert max_in_dictionary({'a': 1, 'b': 5, 'c': 3}) == 5
  assert max_in_dictionary({'x': 10, 'y': 20, 'z': 15}) == 20
  assert max_in_dictionary({'k1': 100, 'k2': 30, 'k3': 50}) == 100
output: def max_in_dictionary(d):
      return max(d.values())