You are standing on top of an amazing Himalayan mountain. The view is absolutely breathtaking! you want to take a picture on your phone, but... your memory is full again! ok, time to sort through your shuffled photos and make some space...
Given a gallery of photos, write a function to sort through your pictures.
You get a random hard disk drive full of pics, you must return an array with the 5 most recent ones PLUS the next one (same year and number following the one of the last).
You will always get at least a photo and all pics will be in the format `YYYY.imgN`
Examples:
```python
sort_photos["2016.img1","2016.img2","2015.img3","2016.img4","2013.img5"]) ==["2013.img5","2015.img3","2016.img1","2016.img2","2016.img4","2016.img5"]
sort_photos["2016.img1"]) ==["2016.img1","2016.img2"]
```
def key(pic):
    parts = pic.split('.')
    return parts[0], int(parts[1][3:])

def sort_photos(pics):
    pics.sort(key=key)
    pics = pics[-5:]
    last_key = key(pics[-1])
    pics.append(last_key[0] + '.img' + str(last_key[1] + 1))
    return pics
def key(pic):
    parts = pic.split('.')
    return parts[0], int(parts[1][3:])

def sort_photos(pics):
    pics.sort(key=key)
    pics = pics[-5:]
    last_key = key(pics[-1])
    pics.append(last_key[0] + '.img' + str(last_key[1] + 1))
    return pics