input: Write a function to convert degrees Fahrenheit to degrees Celsius. The function should take a single parameter representing the temperature in Fahrenheit and return the temperature converted to Celsius.
  assert FahrenheitToCelsius(32) == 0
  assert FahrenheitToCelsius(212) == 100
  assert FahrenheitToCelsius(98.6) == 37
  assert FahrenheitToCelsius(-40) == -40
output: def FahrenheitToCelsius(fahrenheit):
      return (fahrenheit - 32) * 5 / 9