input: Write a function to compute the sum of the values of a given dictionary. If the dictionary is empty, return 0.
  
  def dict_sum(dict):
      sum = 0
      for key, value in dict.items():
          sum += value
      return sum if dict else 0
  
  assert dict_sum({'A':5, 'B':6, 'C':10}) == 21
  assert dict_sum({'X':1, 'Y':2, 'Z':3}) == 6
  assert dict_sum({}) == 0
output: def dict_sum(dict):
      sum = 0
      for key, value in dict.items():
          sum += value
      return sum if dict else 0