input: Write a function to compute the sum of the values of a given dictionary. If the dictionary is empty, the function should return 0.
  
  assert dict_sum({'A': 5, 'B': 6, 'C': 10}) == 21
  assert dict_sum({'X': 3, 'Y': 7, 'Z': 9}) == 19
  assert dict_sum({}) == 0
  assert dict_sum({'Q': 1}) == 1
  assert dict_sum({'A': 10, 'B': 20, 'C': 30}) == 60
output: def dict_sum(d):
      return sum(d.values())