Question: I am attempting to initialize a list and keep getting the index out of range:

```
self.nodes = [[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]]

```

When I run this code:

```
for i in range(self.rows):
            for j in range(self.columns):
                if self.GRID[i][j] == 0:
                    self.walkable.append(Node(j * self.cellSize, i * self.cellSize))
                    self.isWalkable = True
                if self.GRID[i][j] == 1:
                    self.unwalkable.append(Node(j * self.cellSize, i * self.cellSize))
                    self.isWalkable = False
                if self.GRID[i][j] == 2:
                    self.player = Node(j * self.cellSize, i * self.cellSize)
                    self.isWalkable = True
                if self.GRID[i][j] == 3:
                    self.npc = Node(j * self.cellSize, i * self.cellSize)
                    self.isWalkable = True

                self.nodes[i][j] = Node(j, i)
                self.nodes[i][j].setWalkable(self.isWalkable)

```

The error I get is:

```
self.nodes[i][j] = Node(j, i)
IndexError: list assignment index out of range

```

Answer: 
What is `Node()` ?

```
>>> nodes = [[],[],[],[],[],[],[],[],[],[],[],[],[],[],[],[]]
>>> nodes[0][0] = 5
Traceback (most recent call last):
  File "<interactive input>", line 1, in <module>
IndexError: list assignment index out of range
>>> nodes[0].append(5)
>>> nodes
[[5], [], [], [], [], [], [], [], [], [], [], [], [], [], [], []]

```
```
self.nodes = [[[]] * self.columns] * self.rows

```