input: Write a function to convert degrees Fahrenheit to degrees Celsius. If the input temperature is invalid (i.e., not a number), the function should return None.
  def FahrenheitToCelsius(temp_fahrenheit):
      if not isinstance(temp_fahrenheit, (int, float)):
          return None
      temp_celsius = (temp_fahrenheit - 32) * 5/9
      return temp_celsius
  
  assert FahrenheitToCelsius(32) == 0
  assert FahrenheitToCelsius(212) == 100
  assert FahrenheitToCelsius('thirty-two') == None
  assert FahrenheitToCelsius(-40) == -40
output: def FahrenheitToCelsius(temp_fahrenheit):
      if not isinstance(temp_fahrenheit, (int, float)):
          return None
      temp_celsius = (temp_fahrenheit - 32) * 5/9
      return temp_celsius