CS计算机代考程序代写 python “””
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QUESTION 1: General Knowledge
10 marks, ~8 minutes
(a) Consider a method of some class that has the following signature:
def mystery(self, m1: int, m2: List[int]) -> Optional[Dict[int, List[int]]]:
# docstring and implementation hidden
On a given call to this method, we observe that the method returns None.
Explain briefly whether returning None implies a violation of each of the
following (e.g., provide and justify your answer for each of these 3 following
concepts):
– Does it imply a violation of the Representation Invariant of the class?
TODO: your answer and justification
– Does it imply a violation of the precondition of mystery()?
TODO: your answer and justification
– Does it imply a violation of the the method’s type contract?
TODO: your answer and justification
(b) Consider this piece of code.
1 def blah(lst: List[int]) -> Dict[int, str]:
2 # docstring and implementation hidden
3
4 if __name__ == ‘__main__’:
5 a = [1,2,3]
6 foo = blah(a)
7 if ’42’ in foo:
8 print(“Yes”)
9 else:
10 print(“No”)
Please comment on the possible output of this program, assuming blah() works
correctly.
TODO: your answer here
(c) Consider the following piece of Python code with four lines
1 lst = [1, 2, 3]
2 lst = lst + [4, 5, 6]
3 lst2 = lst
4 lst2.append(lst[:])
In each line, how many _objects_ are created in the Python memory model?
TODO: Fill in your answers below.
Line 1:
Line 2:
Line 3:
Line 4:
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