Whats wrong with my code?

https://www.codecademy.com/en/courses/python-intermediate-en-rCQKw/2/5?curriculum_id=4f89dab3d788890003000096#

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

```
def median(lavuk):
lavuk = sorted(lavuk)
index_number = 0
median_score = 0
for n in lavuk:
index_number = index_number + 1
return index_number
if (index_number % 2) == 0:
median_score =(lavuk[(index_number/2.0)]+lavuk[(index_number/2.0)+1])/2.0
else:
median_score = lavuk[(index_number + 1) / 2.0]
return median_score
```