About the implementation of del in Python 3

[Dan Wissme]

I thought that del L[i] would slide L[i+1:] one place to the left, 
filling the hole, but :

 >>> L
[0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
 >>> id(L)
4321967496
 >>> id(L[5])    # address of 50 ?
4297625504
 >>> del L[2]
 >>> id(L[4])     # new address of 50 ?
4297625504
 >>> id(L)
4321967496

So the element 50 is still at the same memory location.
What del L[i] do exactly, and what is its complexity ? O(1) or O(n) ?
Thanks,

    dan