I want to manipulate a List in python while keeping the original List untouched.  

So I've substituted the Original List into a new defined variable as below : 

```
Original_List = [1,5]
Substituted_List = Orginal_List

```

But I've noticed doing `Substituted_List.append()` also modify the Original\_List too: 

```
Substituted_List.append(3)
print("Original list is: %s" %Original_List)
print("Substituted list is: %s" %Substituted_List)  

```

The output is: 

```
Original list is: [1,5,3]
Substituted list is: [1,5,3]

```

While the Original list is supposed to be: `[1,5]`