input: Write a python function to calculate the date that is a certain number of days from today.
  assert calculate_future_date(30) == (date.today() + timedelta(days=30))
  assert calculate_future_date(0) == date.today()
  assert calculate_future_date(-10) == (date.today() + timedelta(days=-10))
output: from datetime import date, timedelta
  
  def calculate_future_date(days):
      return date.today() + timedelta(days=days)