input: Write a function to calculate the sum of all values in a given dictionary. If the dictionary is empty, return 0.
  assert compute_dict_sum({"a": 5, "b": 10, "c": 15})==30
  assert compute_dict_sum({})==0
  assert compute_dict_sum({"x": -1, "y": 1})==0
  assert compute_dict_sum({"apple": 2, "banana": 3, "cherry": 5})==10
  assert compute_dict_sum({"one": 1, "two": 2, "three": 3})==6
output: def compute_dict_sum(d):
      return sum(d.values())