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