In one sentence explanation for each class, and each method in each class. Specify the class attributes. Go through the classes in this order:

2. TreeNode
4. Tree

class TreeNode:
   #set node name, list of children and parent name
   def __init__(self, node_name, parent_name):
       self.name = node_name
       self.parent = parent_name
       self.children = {}
       
   #add a child to the node's children dictionary
   def add_child(self, child_name, edge_cost):
       self.children[child_name] = edge_cost
       
   #set the parent name, p is of type string
   def set_parent(self, p):
       self.parent = p
       
   #remove a child from the node's children dictionary
   def remove_child(self, child_name):
       self.children.pop(child_name)
       
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class Tree:
   
   def __init__(self):
       self.nodes = {}
       self.root_name  = ''

   #set the tree root node,
   #r is an object of type TreeNode
   def set_root(self, r):
       self.root_name = r.name
       self.nodes[r.name] = r
       self.nodes[r.name].set_parent(None)
       
   #add a node to the tree.
   #The parent must be known at the time of adding the node.
   #both node and parent records are linked with parent-child relationships to facilitate tree traversal later.
   #child_node is an object of type TreeNode
   #parent_node_name is a string
   def add_child_node(self, child_node, parent_node_name, edge_cost):
       self.nodes[child_node.name] = child_node
       self.nodes[child_node.name].set_parent(parent_node_name)
       self.nodes[parent_node_name].add_child(child_node.name, edge_cost)
       
   '''    
   #add nodes to the tree as children to an already-existing parent node.
   #The parent must be known at the time of adding the node.
   #child nodes and parent records are linked with parent-child relationships to facilitate tree traversal later.
   #parent_node is a string
   #children are stored as a list of tuples (name, edge_wt)
   def add_children_nodes(self, children, parent):
       for child in children:
           child_name = child[0]
           edge_cost = child[1]
           self.nodes[child_name] = TreeNode(child_name,parent)
           self.nodes[child_name].set_parent(parent)
           self.nodes[parent].add_child(child_name, edge_cost)
  '''    
       
   #print the path from the root to some node n
   #n is of type TreeNode
   def print_path(self, n):
       if n.name not in self.nodes:
           print("Node not found!")
           return
       path=[]
       cur_node_name = n.name
       
       while cur_node_name is not None:
           #print("current node name: ", cur_node_name)
           path.append(cur_node_name)
           cur_node_name = self.nodes[cur_node_name].parent
           
           
       path.reverse()
       print("Full Path:\n==========")
       for p in path:
           print (p)
       return