### In the below example:

• The TreeNode class is defined with an __init__ method to initialize each node with a key and set its left and right children to None.
• Nodes are created and connected to form a binary tree.
• The in_order_traversal function performs an in-order traversal of the tree, printing the keys of the nodes in sorted order.
• You can extend this basic structure to implement more complex tree structures, such as binary search trees, n-ary trees, or other specialized tree types based on your requirements.
• If you have specific requirements for the tree structure or functionality, feel free to provide more details, and I can help you tailor the implementation accordingly.
```class TreeNode:
def __init__(self, key):
self.key = key
self.left = None
self.right = None

# Example Usage
# Creating nodes
root = TreeNode(1)
root.left = TreeNode(2)
root.right = TreeNode(3)
root.left.left = TreeNode(4)
root.left.right = TreeNode(5)

# Traversing the tree (In-order traversal)
def in_order_traversal(node):
if node:
in_order_traversal(node.left)
print(node.key, end=" ")
in_order_traversal(node.right)

print("In-order traversal:")
in_order_traversal(root)```

Here’s the textual representation of the binary tree created by the code:

``` 1
/ \
2   3
/ \
4   5
```

### Explanation:

The root of the tree is the node with the key 1.
The left child of 1 is the node with the key 2, and the right child is the node with the key 3.
The left child of 2 is the node with the key 4, and the right child is the node with the key 5.