There're two lists like 

```
[[A, A], [B, B], [C, C], [D, D]]

```

and

```
[[A, A], [B, B]]

```

How to delete list 2 from 1 with result `[[C, C], [D, D]]` and make it without loop, because both lists are very big and loops works slow?

thanks
list examples

```
>>>a = [[9, 9], [8, 8], [7, 7], [6, 6], [4, 4], [5, 5], [12, 12], [15, 15], [2, 2], [3, 3]] 

>>>b = [[4, 4], [5, 5]]

```

form ask to write what I already tried, OK, it's below
Attempt one: (doesn't work, moreover has a loop inside)

```
def rightdotsremowe (ax, bx): 
    for o in set(bx):
        try:
            ax.remove(o) 
        except ValueError:
            pass
    return ax

```

Attempt two (looks better but doesn't work too)

```
newlist00 = [x for x in a if (x not in e)]

```