PCPP1 Practice Test 2 — 10 Questions

Question 1

You are developing a multithreaded HTTP scraper. When using the 'requests' library inside 'threading.Thread' objects, what is the recommended practice for handling session persistence?

Accepted Answer

Initialize a new Session object inside each thread's run method. The requests.Session object is not thread-safe because it maintains shared state such as cookies, connection pools, and headers. Initializing a new Session inside each thread's run method ensures each thread has its own isolated session, avoiding race conditions and data corruption. This is the recommended practice for multithreaded scraping with requests.

Answer

Wrap the session object in a threading.Lock

Answer

Share a single global Session object across all threads

Answer

Disable connection pooling using 'pool_connections=0'

Question 2

You are refactoring code that performs sensitive operations. Which of the following is the most secure practice for handling secret keys?

Accepted Answer

Use environment variables to store sensitive configuration.. Hardcoding secrets is a major security vulnerability; using environment variables is the industry standard.

Answer

Encrypt the secrets and store them as constants in a module.

Answer

Store secrets in a private class attribute.

Answer

Hardcode them as strings inside a 'config.py' file and ignore it in Git.

Question 3

According to PEP 8, what is the maximum recommended length for a line of code?

Accepted Answer

79 characters.. PEP 8 suggests limiting lines to 79 characters to allow multiple files to be opened side-by-side.

Answer

80 characters.

Answer

No limit.

Answer

120 characters.

Question 4

You are writing a Python utility that copies a directory tree to a network share using shutil. You must preserve file metadata and fail loudly if the destination already contains a conflicting file, rather than silently overwriting it. Which TWO shutil features satisfy these requirements? (Choose two.)

Accepted Answer

Leave the default behaviour of shutil.copytree() unchanged so that a pre-existing destination path raises FileExistsError.. Preserving metadata requires a copy function built on copystat, which copy2 provides, and copytree() exposes this through copy_function. Failing loudly on a pre-existing destination is the default copytree() behaviour, since dirs_exist_ok is False unless explicitly set. Together, copy_function=shutil.copy2 and the default dirs_exist_ok value satisfy both stated requirements.

Answer

Pass copy_function=shutil.copyfile to shutil.copytree() so existing files are never overwritten.

Answer

Pass dirs_exist_ok=True to shutil.copytree() so the copy proceeds when the destination directory already exists.

Answer

Pass copy_function=shutil.copy to shutil.copytree() so only permission bits are carried over.

Question 5

You are consuming a REST API that returns data in JSON format. After calling response.json(), you notice the data contains nested dictionaries. What is the most Pythonic way to handle a missing key in the response dictionary safely?

Accepted Answer

Use response.json().get('key', default_value). The dict.get() method provides a way to access a key with a default value if the key does not exist, preventing a KeyError.

Answer

Wrap the access in a try-except KeyError block

Answer

Check 'if 'key' in response.json():' before access

Answer

Use response.json()['key'] and assume the API schema is always correct

Question 6

You are designing a REST client that must call an endpoint protected by OAuth 2.0 using the client credentials grant. The authorization server expects the client identifier and client secret to be sent in the request body as `application/x-www-form-urlencoded`, along with `grant_type=client_credentials`. Which `requests` call correctly obtains the token?

Accepted Answer

requests.post(token_url, data={'grant_type': 'client_credentials', 'client_id': cid, 'client_secret': secret}). OAuth 2.0 token requests use POST with application/x-www-form-urlencoded bodies. The data parameter in requests performs that encoding automatically. Sending the grant type and client credentials in the body, rather than as Basic auth or JSON, satisfies the server's stated expectations and returns the access token needed for subsequent API calls.

Answer

requests.post(token_url, json={'grant_type': 'client_credentials', 'client_id': cid, 'client_secret': secret})

Answer

requests.post(token_url, auth=(cid, secret), data={'grant_type': 'client_credentials'})

Answer

requests.get(token_url, params={'grant_type': 'client_credentials', 'client_id': cid, 'client_secret': secret})

Question 7

In a Tkinter grid layout, you want a button to span across two columns. Which parameter should you use?

Accepted Answer

columnspan=2. The columnspan parameter in the grid() method manager allows a widget to occupy multiple columns.

Answer

span_cols=2

Answer

merge=2

Answer

cols=2

Question 8

Which THREE practices improve documentation maintenance?

Accepted Answer

Updating documentation as part of the code review process.. Option A is correct because integrating documentation updates into the code review process makes doc changes a required, verifiable part of every pull request, so docs stay synchronized with code changes instead of drifting out of date. Option C is correct because following a consistent docstring format such as Google style enforces a uniform structure for parameters, returns, and raises sections, which makes documentation easier to read, review, and parse by tooling. Option E is correct because automatic documentation generation tools like Sphinx build docs directly from source docstrings, so regenerating after each change keeps published documentation current with minimal manual effort. Option B is not correct because writing docs only at the end of a project causes them to lag behind implementation and often results in incomplete or stale content. Option D is not correct because keeping documentation in a separate repository decouples it from the code, making it harder to update in the same commit or review cycle and increasing the risk of version mismatch.

Answer

Writing docs only at the end of the project.

Answer

Keeping documentation in a separate repository.

Question 9

What is the effect of setting __slots__ in a parent class on a child class that does not define its own __slots__?

Accepted Answer

The child class will have a __dict__ attribute, overriding the parent's optimization.. The child class will receive an instance __dict__ unless it also defines __slots__, effectively defeating the memory optimization of the parent.

Answer

The child class will raise an error at instantiation.

Answer

The child class will inherit the memory savings automatically.

Answer

The child class will be unable to add new attributes.

Question 10

What is the consequence of not calling super().__init__() in a class with multiple inheritance?

Accepted Answer

The initialization chain for parent classes is interrupted.. The MRO chain will break, and sibling classes may not be initialized properly, potentially causing missing attributes or logic errors.

Answer

The class will not be created.

Answer

All attributes will be lost.

Answer

Python will raise a RuntimeError.