input: Write a function to compute the sum of all values in a given dictionary containing string keys and integer values. If the dictionary is empty, return 0 as the sum.
  assert compute_dict_sum({"a": 5, "b": 10, "c": 15})==30
  assert compute_dict_sum({"x": 2, "y": 3, "z": 4})==9
  assert compute_dict_sum({})==0
output: def compute_dict_sum(d):
      return sum(d.values()) if d else 0