title: Adding days to a current date python
body: <p>Write a function that helps answer questions like '"Today is Wednesday. I leave on holiday in 19 days time. What day will that be?"' ...So the function must take a day name and a delta argument — the number of days to add — and should return the resulting day name:</p>
  
  <pre><code>def day_add(day, number):
      if number == "0":
          return day
      else:
          return
  
  result = day_add("Thursday", "0")
  print(result)
  
  assert "Friday" == day_add("Monday", "4"), "gives you back the day it will be if you add a certain number of days"
  assert "Tuesday" == day_add("Tuesday", "0"), "gives back the day you put in"
  </code></pre>