binary_tree.py

class BinaryNode:
    __slots__ = ("value", "left", "right")
    def __init__(self, value=None, left=None, right=None):
        self.value = value
        self.left = left
        self.right = right
        
    def __repr__(self):
        return f"<BinaryNode value={self.value}; {1 if self.left else 0 + 1 if self.right else 0} children>"
    
    def inorder(self):
        if self.left:
            for value in self.left.inorder():
                yield value
        yield self.value
        if self.right:
            for value in self.right.inorder():
                yield value
    
    def preorder(self):
        yield self.value
        if self.left:
            for value in self.left.preorder():
                yield value
        if self.right:
            for value in self.right.preorder():
                yield value
    
    def postorder(self):
        if self.left:
            for value in self.left.postorder():
                yield value
        if self.right:
            for value in self.right.postorder():
                yield value
        yield self.value