input: Write a function to find the maximum value within a nested dictionary. 
  
  def findMaxValue(dict):
      max_val = None
      for key, value in dict.items():
          if isinstance(value, dict):
              max_val = max(findMaxValue(value), max_val)
          else:
              max_val = max(value, max_val)
      return max_val
  
  assert findMaxValue({})==None
  assert findMaxValue({"a": 1, "b": 2})==2
  assert findMaxValue({"a": 1, "b": {"c": 3, "d": 4}})==4
  assert findMaxValue({"a": 1, "b": {"c": {"d": 5}}})==5
  assert findMaxValue({"a": {"b": {"c": {"d": [6, 7]}}, "e": 8}})==8
output: def findMaxValue(dict):
      max_val = None
      for key, value in dict.items():
          if isinstance(value, dict):
              max_val = max(findMaxValue(value), max_val)
          else:
              max_val = max(value, max_val)
      return max_val