求解决以下python出现的问题，要做出如何修改才能运行成功呢？
下面是我的代码和错误信息：
# 1. Implement a class named "MyClass"
# This class should have:
# * During instantiation of this class, the 'some_val' parameter should be set as
# a variable with the same name in the instance
# * Implement the method called 'plus_n' that takes one parameter (named 'n'), such that
# it should return the sum of instance's 'some_val' variable and 'n'
class MyClass:
def __init__(self, some_val):
self.some_val = some_val
def plus_n(self, n):
return self.some_val + n
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# 2. Given two classes 'Animal' and 'DigestiveSystem, implement, using COMPOSITION the method 'eat_food' in the 'Animal' class.
# * Animal instances should have a 'diggestive_system' attribute, which is the DigestiveSystem instance of that object.
# * The eat_food method should PROCESS any 'food' (any string) that are not allergenic (use the method 'has_allergy' to check for this case)
# * The DigestiveSystem is a class responsible for the PROCESS of any food eaten,
# so make use of this in the Animal.eat_food method (remember COMPOSITION!)
class DigestiveSystem:
"""This class is already done for you
don't changea any code on it.
"""
def process_food(self, food):
return f'processed-{food}'
class Animal:
def __init__(self):
self.digestive_system = DigestiveSystem()
def has_allergy(self, food):
if food.lower() in ['peanut', 'milk']:
return True
return False
def eat_food(self, food):
if not self.has_allergy(food):
return self.digestive_system.process_food(food)
else:
return f"{food} is allergenic and cannot be eaten"
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# 3. Rewrite the Human class bellow (without changing it's name), so that it inherits from the Animal class of the exercice 2.
# * You should override the 'has_allergy' method in the Human class, so that it now only returns True if the food is 'peanut'
class Human(Animal):
def has_allergy(self, food):
return food == "peanut"
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# 4. Implement the Child class below, which inherets from Human (from exercice 3).
# * Instances of Child need to have a 'toy' attribute (string), which is defined during instantiation
# * This class should also have a 'playing_with_toy' method, which should return the 'toy' (string) that the Child has.
# * Other than that, a Child should behave exactly like a Human instance, so make sure it is inheriting all the logic from its parents '__init__' method
class Child(Human):
def __init__(self, toy, *args, **kwargs):
self.toy = toy
super().__init__(*args, **kwargs)
def playing_with_toy(self):
return self.toy
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# 5. Write code in the following __main__ function to test all classes, their attributes and functions.
# * Currently this function includes some examples tests, so you need to extend this code to include all needed tests.
if __name__ == '__main__':
# Example code for testing
# Problem 1 - Test
my_instance = MyClass(some_val=90)
assert my_instance.some_val == 90
another_instance = MyClass(some_val=100)
assert another_instance.plus_n(3) == 103
# Problem 2 - Test
digestive_system = DigestiveSystem()
animal = Animal(digestive_system)
assert isinstance(animal.digestive_system, DigestiveSystem)
assert animal.eat_food("banana") == "banana has been processed."
assert animal.eat_food("peanut") is None
# Problem 3 - Test
human = Human(digestive_system)
assert human.has_allergy("peanut") == True
assert human.has_allergy("banana") == False
assert human.eat_food("banana") == "banana has been processed."
assert human.eat_food("peanut") is None
# Problem 4 - Test
child = Child("car", "peanut", digestive_system)
assert child.playing_with_toy() == "car"
assert child.has_allergy("peanut") == True
assert child.has_allergy("banana") == False
assert child.eat_food("chocolate") == "chocolate has been processed."
assert child.eat_food("peanut") is None
错误代码是：
