__setattr__
here’s a trivial person class
class Person:
def __init__(self, name, age):
self.name = name
self.age = age
notice that you can add any attribute to an instance of person
terry = Person('Terry Gilliam', 78)
terry.new_attribute = 'lets make sure this fails'
print(terry.new_attribute) # 'lets make sure this fails'
can you modify class Person so that it disallows adding any new attributes beyond .name and .age?
hint: add a
__setattr__(self, name, value)function to Person
the following code should succeed:
terry = Person('Terry Gilliam', 78)
terry.age = terry.age + 1
print(terry.age) # 79
ok = False
try:
terry.new_attribute = 'lets make sure this fails'
except:
ok = True
print('good')
assert ok
### useful test - the following code should succeed
terry = Person('Terry Gilliam', 78)
terry.age = terry.age + 1
print(terry.age) # 79
ok = False
try:
terry.new_attribute = 'lets make sure this fails'
except:
ok = True
print('good')
assert ok