This code fails on the check when given the list: [4,5,5,4]

It raises the following error:

Oops, try again. median([4, 5, 5, 4]) returned 5.0 instead of 4.5

As I understand it, the median of lists of even length is the average of the two middle elements.

I'm sure the average of the two middle elements (5 and 5, in this case) of the given list is 5, not 4.5.

```
def median( lst ):
mid_index = len(lst) // 2
mid_val = lst[ mid_index ]
# list length is even
if len( lst ) % 2 == 0:
return (mid_val + lst[ mid_index - 1 ]) / 2.0
# list length is odd
else:
return mid_val
```

Thanks in advance for the help.