如何用for循环简化有规律的if代码

代码复杂化了 !

from copy import deepcopy

line = {'child':[1]}
tree = [{'child':[1]}]

for current_layer in range(1, 4):
    subtree = tree
    for j in range(current_layer):
        subtree = subtree[-1]['child']
    subtree.append(deepcopy(line))

print(tree)

[{'child': [1, {'child': [1, {'child': [1, {'child': [1]}]}]}]}]

current_node = tree[-1]
for layer in range(current_layer - 1):
    current_node = current_node['child'][-1]
current_node['child'].append(line)