input: Write a function to convert degrees Fahrenheit to degrees Celsius. The function takes a single parameter, temp_fahrenheit, which represents the temperature in Fahrenheit, and returns the temperature in Celsius.
  assert FahrenheitToCelsius(32)==0
  assert FahrenheitToCelsius(212)==100
  assert FahrenheitToCelsius(-40)==-40
  assert FahrenheitToCelsius(98.6)==37
output: def FahrenheitToCelsius(temp_fahrenheit):
      return (temp_fahrenheit - 32) * 5 / 9