Я не понимает, там ошибка
Traceback (most recent call last):
File "D:/python/lambda.py", line 13, in <module>
for funciton in callbacks : print('result:' , function(3))
NameError: name 'callbacks' is not defined

def square(x):
....return x ** 2
square = lambda x : x ** 2
def function_1():
....def function_2():
........callbacks = [ function_1 , function_2 ]
........callbacks = [lambda : function_1 , lambda : function_2]
........def function_1(x) : return x ** 2
........def function_2(x) : return x ** 3
........def function_3(x) : return x ** 4
....callbacks = [function_1 , function_2 , function_3]
....print('\nNamed function:')
for funciton in callbacks : print('result:' , function(3))
callbacks = \
[lambda x : x ** 2 , lambda x : x ** 3 , lambda x : x ** 4]
print('\nAnonymous Function:')
for funciton in callbacks : print('result:' , function(3))