I need to be able to duplicate a list of lists in python.

so for example right now I have a function that returns a list.

this is always lists within a list. 

for example: 

```
 myList = [[1,2,3],[4,5,6],[7,8,9]]

```

now I need to create two copies of this list (myList1, and myList2), each of which is separately mutable (for example, if I edit myList1, myList2 will not be edited)

I have tried everything. 

from the simple:

```
 myList1 = myList[:]
 myList2 = myList[:]

```

to the more complicated:

```
 myList1 = []
 for ch in myList:
      myList1.append(ch)

 myList2 = []
 for ch in myList:
      myList2.append(ch)

```

nothing works. If I change a value in one list:

```
 myList1[0][0] = 10

```

both lists become:

```
 [[10,2,3],[4,5,6],[7,8,9]]

```

Any idea how to do this?