I'm trying to transfer items from one list to the other (like below) but the result is really puzzling. Does anyone have an idea what's going on here??

```
l1=range(1,11)
l2=[]
for i in l1:
    if i>=6:
        l2.append(i)
        l1.remove(i)
print l1
print l2

l1 = [1-5, 7, 9] # and
l2 = [6, 8, 10]  # !!

```