tree.py

class Tree:
    def __init__(self):
        self.nodes = []
        self.root = None
    
    def add_node(self, node=None):
        if node:
            self.nodes.append(node)
    
    def list_nodes(self):
        # need to recurse here...
        for n in self.nodes:
            print("parent -- ", n.parent)
            print("name", n.name)
            if len(n.children):
                for c in n.children:    
                    c.list_children()    
                    print("children", c.name)
            print('-----------------------')


class Node:
    def __init__(self, name=None, parent=None):
        self.name = name
        self.parent = parent
        self.children = []
    
    def add_node(self, node=None):
        if node:
            self.children.append(node)
    
    def list_children(self):        
        for c in self.children:
            print(c.name)
    
    def get_level(self):
        return 

class Solution:

    tree = Tree()

    def __init__(self):
        return

    def build_tree(self, arr):
        
        for a in arr:  
            n = Node(name=a[1], parent=a[0])         
            self.tree.add_node(n)  
            self.balance(n)
                                
        print(self.tree.list_nodes())    

    def balance(self, node):        
        for n in self.tree.nodes:
            if n.parent == node.name:
                self.tree.nodes.remove(n)
                node.add_node(n)
                self.balance(node)                

a = Solution()
a.build_tree([
    ["dog", "poodle"],  
    ["dog", "pomeranian"], 
    ["canine", "dog"], 
    ["canine", "wolf"],
    ["feline", "cat"], 
    ["cat", "persian"],          
    ["mammal", "feline"],     
    ["mammal", "canine"], 
    ["reptile", "crocodile"], 
    ["feline", "jaguar"],  
    ["reptile", "iguana"], 
    ["feline", "lion"], 
    ["mammal", "monotreme"], 
    ["dog", "st bernard"], 
    ["reptile", "turtle"]
]
)