input: Write a function to find the maximum value within a nested dictionary. Include the function header, assert statements, and the expected outputs for the tests.
  
  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({"key1": {"value1": 10, "value2": 20}, "key2": {"value3": 40}}) == 40
  assert findMaxValue({"a": 5, "b": {"c": 30, "d": {"e": 45}}}) == 45
  assert findMaxValue({"x": {}, "y": {"z": 10}}) == 10
  assert findMaxValue({}) == None
  assert findMaxValue({"key1": {"value1": 70, "value2": 60}, "key2": {"value3": 65}}) == 70
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