input: Write a python function to sum the values of each key in a dictionary.
  assert sum_dict_values({1: [5, 6, 7, 8], 2: [5, 6, 7, 8], 3: [5, 6, 7, 8], 4: [5, 6, 7, 8]}) == {1: 26, 2: 26, 3: 26, 4: 26}
  assert sum_dict_values({1: [1, 2, 3], 2: [4, 5, 6], 3: [7, 8, 9]}) == {1: 6, 2: 15, 3: 24}
  assert sum_dict_values({1: [10, 20], 2: [30, 40], 3: [50, 60]}) == {1: 30, 2: 70, 3: 110}
output: def sum_dict_values(d):
      return {k: sum(v) for k, v in d.items()}