input: Write a function to convert a temperature from degrees Fahrenheit to degrees Celsius. The function should take a single argument representing the temperature in Fahrenheit and return the temperature in Celsius. If the input temperature is negative, the function should still return the correct conversion.
  assert FahrenheitToCelsius(32)==0
  assert FahrenheitToCelsius(212)==100
  assert FahrenheitToCelsius(-40)==-40
  assert FahrenheitToCelsius(0)==-17.77777777777778
  assert FahrenheitToCelsius(50)==10
output: def FahrenheitToCelsius(fahrenheit):
      return (fahrenheit - 32) * 5 / 9