input: from typing import Union
  
  def findMaxValue(nested_dict: dict) -> Union[int, float, None]:
      """Find the maximum value within a nested dictionary.
      >>> sample_dict = { "key1": { "value1": 10, "value2": 20 }, "key2": { "value3": 40 } }
      >>> findMaxValue(sample_dict)
      40
      """
      max_val = None
      for key, value in nested_dict.items():
          if isinstance(value, dict):
              max_val = max(findMaxValue(value), max_val)
          else:
              max_val = max(value, max_val)
      return max_val
output:     max_val = None
      for key, value in nested_dict.items():
          if isinstance(value, dict):
              max_val = max(findMaxValue(value), max_val)
          else:
              max_val = max(value, max_val)
      return max_val