PCPP1 Practice Test 5 — 25 Questions

Question 1

You are creating a class where you want to prevent instances from having a __dict__ to save memory. You add __slots__ = ('x', 'y') to the class. Which statement is true about this class?

Accepted Answer

Instances of the class will not have a __dict__ and can only have attributes x and y.. The __slots__ declaration restricts instances to the named attributes and eliminates the per-instance __dict__, saving memory. Only attributes listed in __slots__ can be assigned; others raise AttributeError. Subclasses do not automatically inherit this restriction unless they also define __slots__.

Answer

The class can still accept arbitrary attributes, but they will be stored in a separate dictionary.

Answer

Instances will still have a __dict__, but x and y will be stored in slots for faster access.

Answer

Subclasses of this class will also be prevented from having a __dict__ automatically.

Question 2

You wish to group several widgets together within a frame. Which widget acts as a container for this purpose?

Accepted Answer

tk.Frame(). The Frame widget is specifically designed as a container to group other widgets.

Answer

tk.Group()

Answer

tk.Box()

Answer

tk.Container()

Question 3

You are using the sqlite3 module to manage a database. You need to ensure that database changes are permanently saved even if your script terminates unexpectedly. Which method should you call after an INSERT operation?

Accepted Answer

connection.commit(). The commit() method on a connection object is required to save changes permanently in sqlite3.

Answer

connection.save()

Answer

cursor.flush()

Answer

connection.close()

Question 4

Which THREE of the following are standard ways to handle API authentication?

Accepted Answer

OAuth 2.0. OAuth 2.0 (A) is a standard authorization framework that issues access tokens via grant flows (authorization code, client credentials, etc.), allowing scoped, revocable API access without sharing credentials. API Keys (B) are a widely used standard mechanism where a unique key identifies and authenticates the calling application, typically passed in a header or query parameter. Basic Authentication (D) is an HTTP-standard scheme (RFC 7617) that sends a Base64-encoded username:password in the Authorization header, commonly used for simple API authentication over TLS. Public IP Whitelisting (C) is a network access control, not an authentication method, since it does not verify caller identity. Hardcoding passwords in code (E) is an insecure anti-pattern that exposes credentials and is not a standard authentication approach.

Answer

Public IP Whitelisting

Answer

Hardcoding passwords in code

Question 5

Which THREE of the following are potential pitfalls of the Singleton pattern in Python?

Accepted Answer

They introduce global state.. Option B is correct because a Singleton stores its single instance in a class-level or module-level location, effectively creating global mutable state that any part of the program can read or modify, which increases coupling and makes behavior harder to reason about. Option C is correct because Singleton clients typically call a hard-coded accessor such as getInstance() or reference a module-level instance directly, so you cannot easily substitute an alternative implementation through constructor injection or a DI container. Option D is correct because that same hard-coded access and shared state persist across tests, so tests can leak state into one another and cannot easily isolate the class under test with a mock or fake. Option A is wrong because Singletons can participate in inheritance (subclasses can inherit or override the instance accessor), even if doing so is awkward. Option E is wrong because a naive Singleton implementation is not automatically thread-safe; without a lock or other synchronization, two threads can race and create multiple instances.

Answer

They cannot be used with inheritance.

Answer

They are always thread-safe.

Question 6

Which THREE features are associated with robust logging in production applications?

Accepted Answer

Log rotation to prevent disk space exhaustion.. Option A is correct because log rotation (e.g., via logrotate or size/time-based rolling appenders) caps log file growth and prevents disk space exhaustion, which is a core production reliability concern. Option C is correct because structured output (e.g., JSON formatters) makes logs machine-parseable, enabling reliable aggregation, searching, and alerting in tools like the ELK stack or Splunk. Option D is correct because using different logging levels per environment (e.g., DEBUG in development, WARN or ERROR in production) controls verbosity, reduces noise and cost, and keeps production logs actionable. Option B is not inherently a robust-logging feature: writing only to stdout can be valid in containerized setups, but 'exclusively' excludes durable file or remote sinks and is not a defining best practice. Option E is incorrect because including personal user data in logs risks privacy violations (e.g., GDPR) and security exposure, so it should be avoided or masked.

Answer

Logging to 'stdout' exclusively.

Answer

Including personal user data in logs.

Question 7

A Python developer is reviewing code and notices that a function has a default argument value set to an empty list: `def append_to(element, target=[]):`. According to best practices, what is the recommended way to handle mutable default arguments?

Accepted Answer

Use `None` as the default and create a new list inside the function if needed.. Mutable default arguments are evaluated once at function definition, leading to shared state. The recommended practice is to use None as the default and create a new mutable object inside the function when needed. This ensures each call gets a fresh object unless one is explicitly passed.

Answer

Keep the empty list as the default; Python handles it safely.

Answer

Use a tuple instead of a list as the default value.

Answer

Define the default argument inside the function body instead.

Question 8

Which TWO practices ensure secure handling of sensitive environment configurations?

Accepted Answer

Add '.env' to your '.gitignore' file.. Option D is correct because adding '.env' to '.gitignore' prevents the file containing sensitive configuration values from being tracked and pushed to the Git repository, keeping secrets out of version control history. Option E is correct because using a library like 'python-dotenv' loads configuration from a local '.env' file into environment variables at runtime, so secrets stay out of source code and can be managed per-environment. Options A and C are insecure because committing '.env' files to the repository or emailing them exposes secrets to unintended parties and version history. Option B is also wrong since storing secrets in code comments still embeds them in source code that may be shared or committed.

Answer

Commit .env files to the code repository.

Answer

Store secrets in code comments.

Answer

Share the '.env' file via email.

Question 9

Which THREE of the following are valid HTTP request methods commonly used in RESTful API design?

Accepted Answer

DELETE. GET (C), POST (D), and DELETE (B) are all standard HTTP request methods defined in RFC 7231 and are core to RESTful API design: GET retrieves a representation of a resource, POST creates a new resource or submits data to be processed, and DELETE removes the specified resource. These methods map directly to REST's CRUD semantics (Read, Create, Delete) and are idempotent or non-idempotent as appropriate (GET and DELETE are idempotent, POST is not). SEND (A) and FETCH (E) are not valid HTTP request methods; FETCH is a JavaScript browser API for making network requests, and SEND is not part of the HTTP method registry, so neither belongs in a RESTful API design discussion.

Answer

SEND

Answer

FETCH

Question 10

Which THREE of the following represent common issues when using __slots__?

Accepted Answer

Subclasses must define their own __slots__ to avoid creating a __dict__.. Option A is correct because if a subclass does not declare its own __slots__, Python automatically gives it a __dict__, defeating the memory-saving purpose of __slots__ in the parent class. Option B is correct because __slots__ restricts instances to only the named attributes, so assigning any new attribute not listed raises an AttributeError. Option E is correct because defining __slots__ removes the per-instance __dict__ by default, which is the primary mechanism for saving memory. Option C is wrong because __slots__ works fine with most decorators such as @property, @staticmethod, and @classmethod. Option D is wrong because __slots__ does not prevent multiple inheritance; it only imposes constraints when multiple bases have non-empty __slots__ with conflicting slot names.

Answer

They are incompatible with all decorators.

Answer

They prevent the use of multiple inheritance.

Question 11

Which TWO of the following are true regarding multiple inheritance in Python?

Accepted Answer

super() is used for cooperative method calls.. Option B is correct because in Python's multiple inheritance, super() does not simply call the parent class but follows the Method Resolution Order to invoke the next class in the chain, enabling cooperative multiple inheritance where each class's method calls super() to pass control along the MRO. Option D is correct because Python resolves the method resolution order for multiple inheritance using the C3 linearization algorithm, which produces a consistent, monotonic ordering that respects local precedence and subclass relationships. Option A is incorrect because Python explicitly supports multiple inheritance, allowing a class to inherit from several base classes. Option C is incorrect because the MRO is computed at class creation time (when the class is defined), not dynamically at runtime for each method call. Option E is incorrect because composition is often preferred over multiple inheritance for maintainability and avoiding the diamond problem; multiple inheritance is not always preferred.

Answer

It is not supported.

Answer

The MRO is determined at runtime.

Answer

Multiple inheritance is always preferred over composition.

Question 12

Which attribute of a Button widget controls the text displayed on it?

Accepted Answer

text. The 'text' parameter defines the display label of the button.

Answer

value

Answer

caption

Answer

label

Question 13

Which THREE of the following are valid ways to pass data to a REST API using 'requests'?

Accepted Answer

json. Option A, json, is correct because passing a Python object to the json= parameter serializes it to JSON and sends it in the request body with Content-Type: application/json, which is the standard way to submit JSON payloads to a REST API. Option D, params, is correct because params= appends a dictionary of key/value pairs as a URL query string (e.g., ?key=value), which REST APIs commonly use for filtering, pagination, or search arguments. Option E, data, is correct because data= sends a dictionary or bytes as the request body, typically form-encoded (application/x-www-form-urlencoded) for POST/PUT/PATCH requests to REST endpoints. Option B, socket, is not a requests parameter at all — it refers to low-level network programming, not the requests library's API. Option C, url, is not a data-passing mechanism; the url argument specifies the endpoint address, not the payload or query data itself.

Answer

socket

Answer

url

Question 14

When is it acceptable to ignore PEP 8 guidelines?

Accepted Answer

When necessary to maintain consistency with existing code or for legacy reasons.. PEP 8 itself states that project consistency and backward compatibility may warrant exceptions to the rules.

Answer

Only when you disagree with the stylistic choice.

Answer

Never.

Answer

When you are writing a script that will only be used once.

Question 15

You want to execute multiple SQL statements at once in sqlite3. Which method should you use?

Accepted Answer

cursor.executescript(). The executescript() method allows executing multiple SQL statements separated by semicolons.

Answer

connection.execute_all()

Answer

cursor.execute_script()

Answer

cursor.execute_many()

Question 16

When designing a class hierarchy, what is the best way to prevent a method from being overridden by subclasses?

Accepted Answer

Using the @final decorator from typing.. The @final decorator from the typing module (PEP 591) is the standard, type-checker-enforced way to mark a method as non-overridable in Python. When applied to a method, static type checkers like mypy or Pyright will flag any subclass that attempts to override it, and applying @final to a class prevents subclassing entirely. Python itself does not enforce this at runtime, but the decorator is the idiomatic, documented mechanism for expressing the intent.

Answer

Defining it as a private method.

Answer

Defining it as a static method.

Answer

Using the 'final' keyword.

Question 17

When implementing the Singleton pattern, what is the advantage of using a module-level instance over a class-based Singleton?

Accepted Answer

It is simpler and leverages Python's built-in module caching mechanism.. Python modules are naturally Singletons because they are initialized only once upon the first import.

Answer

It is more secure.

Answer

It allows multiple instances if needed.

Answer

It supports lazy loading.

Question 18

What happens when you add two objects of a class that implements __add__?

Accepted Answer

The __add__ method is called.. The __add__ method is automatically called by the interpreter when the '+' operator is used.

Answer

It does nothing.

Answer

It concatenates the objects.

Answer

It raises a TypeError.

Question 19

How do you access the value of a StringVar associated with an Entry widget?

Accepted Answer

var.get(). The get() method is used on the StringVar object to retrieve its current value.

Answer

var.retrieve()

Answer

var.content()

Answer

var.value

Question 20

Which TWO of the following are commonly used for debugging REST API integrations?

Accepted Answer

Using a proxy tool to inspect traffic. Option D is correct because a proxy tool (e.g., Charles Proxy, Fiddler, or mitmproxy) acts as an intercepting man-in-the-middle that captures and displays the actual HTTP/HTTPS requests and responses, letting you inspect methods, URLs, status codes, and payloads for REST debugging. Option E is correct because logging request and response headers (e.g., Content-Type, Authorization, Accept, and custom headers) reveals exactly what the client sent and what the server returned, which is essential for diagnosing issues like missing auth tokens, wrong content negotiation, or unexpected status codes. The remaining options do not belong: hardcoding all credentials (A) is a security anti-pattern that exposes secrets and does nothing to aid debugging, deleting the socket library (B) would break networking entirely, and increasing the CPU clock speed (C) is a hardware performance tweak unrelated to inspecting or troubleshooting API traffic.

Answer

Hardcoding all credentials

Answer

Deleting the socket library

Answer

Increasing the CPU clock speed