input: Write a function to compute the sum of the values of a given dictionary.
  
  def dict_sum(dict):
      sum = 0
      for key, value in dict.items():
          sum += value
      return sum
  
  assert dict_sum({'A':5, 'B':6, 'C':10})==21
  assert dict_sum({'X':1, 'Y':2, 'Z':3})==6
  assert dict_sum({})==0
  assert dict_sum({'P':10, 'Q':20, 'R':30})==60
  assert dict_sum({'M':0, 'N':0, 'O':0})==0
output: def dict_sum(dict):
      sum = 0
      for key, value in dict.items():
          sum += value
      return sum