 Hi everyone, in this video, we are going to see what will happen if we try to use equal sign or assignment operator in order to copy existing list to another one. And we'll see why you must avoid assignment operator if you want to make a new copy of existing list. Let's make one simple example, in which I'll show you what happens if you're using assignment operator. First let's make a list, my list with values 1, 2 and 3. Then let's make my list 1 and let's assign my list to this new list. We'll assign my list to our new list, my list 1. Now I'll type my list 1 to see which elements my list 1 list has. It also has elements 1, 2 and 3 same as my list. What happens if I want to add a new element to my list 1? For example, let's say that we want to add number 4 to our list. So we'll say my list 1 dot append number 4. After doing that, I'll want to see how now my list 1 looks like. Let's see my list 1 and as you can see my list 1 now has elements 1, 2, 3 and 4. If I type my list to see now elements of my list list, what I will see is that our old list my list now has new element 4 same as my list 1. But we have never added element 4 to my list, we have added to my list 1. Some with copying lists with assignment operator is that old and new list are referring to the same list. They both are working with same list. If I change my list 1 then my list will be changed also and vice versa. So if you want to make new copy of list, you must avoid assignment operator because that new list will be referring to the same data as new list. That's all in this video. In next video I will show you how to solve this problem and how to make a new copy of existing list without having problem with referring two lists to the same list.