请将上述代码整合成一个完整的代码

以下是整合后的完整代码：

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

class BinaryTree:
    def __init__(self):
        self.root = None
    
    def insert(self, value):
        new_node = Node(value)
        if self.root is None:
            self.root = new_node
        else:
            current_node = self.root
            while True:
                if value < current_node.value:
                    if current_node.left is None:
                        current_node.left = new_node
                        break
                    else:
                        current_node = current_node.left
                elif value > current_node.value:
                    if current_node.right is None:
                        current_node.right = new_node
                        break
                    else:
                        current_node = current_node.right

    def inorder_traversal(self, node):
        if node is not None:
            self.inorder_traversal(node.left)
            print(node.value)
            self.inorder_traversal(node.right)

    def preorder_traversal(self, node):
        if node is not None:
            print(node.value)
            self.preorder_traversal(node.left)
            self.preorder_traversal(node.right)

    def postorder_traversal(self, node):
        if node is not None:
            self.postorder_traversal(node.left)
            self.postorder_traversal(node.right)
            print(node.value)

# Test
tree = BinaryTree()
tree.insert(4)
tree.insert(2)
tree.insert(1)
tree.insert(3)
tree.insert(6)
tree.insert(5)
tree.insert(7)

print("Inorder traversal:")
tree.inorder_traversal(tree.root)

print("Preorder traversal:")
tree.preorder_traversal(tree.root)

print("Postorder traversal:")
tree.postorder_traversal(tree.root)