I'm trying to implement an iterative inorder traversal of a binary tree. 

node.py:

```
class Node:
 def __init__(self, node=None, left=None, right=None):
 self.node = node
 self.left = left
 self.right = right
```

inorder_traversal.py:

```
def in_order(root):
 stack = nodes = []
 while stack or root:
 if root:
 stack.append(root)
 root = root.left
 else:
 current = stack.pop()
 nodes.append(current.node)
 root = current.right
 return nodes


def main():
 '''
 Construct the below binary tree:

 15
 / \
 / \
 / \
 10 20
 / \ / \
 8 12 16 25

 '''
 root = Node(15)
 root.left = Node(10)
 root.right = Node(20)
 root.left.left = Node(8)
 root.left.right = Node(12)
 root.right.left = Node(16)
 root.right.right = Node(25)

 print(in_order(root))

if __name__ == '__main__':
 main()
```

I've been getting: **AttributeError: 'int' object has no attribute 'node'**.

How can I resolve this error?