Solve the programming task below in a Python markdown code block.
Round any given number to the closest 0.5 step

I.E.
```
solution(4.2) = 4
solution(4.3) = 4.5
solution(4.6) = 4.5
solution(4.8) = 5
```

Round **up** if number is as close to previous and next 0.5 steps.

```
solution(4.75) == 5
```
Also feel free to reuse/extend the following starter code:
```python
def solution(n):
```