PCPP2 Design Patterns Practice Question
Which TWO of the following are common risks when implementing the Singleton pattern in Python?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Race conditions in multi-threaded environments during instantiation
Global state and threading issues are the most prominent risks when implementing the Singleton pattern.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Incompatibility with the abc module
Why it's wrong here
Singletons can be combined with ABCs easily.
- ✗
Excessive subclassing of the Singleton class
Why it's wrong here
Subclassing is not an inherent risk, nor is it common for Singletons.
- ✓
Race conditions in multi-threaded environments during instantiation
Why this is correct
Without locking, two threads could create two instances simultaneously.
- ✓
Hidden global state dependencies throughout the codebase
Why this is correct
Singletons are essentially global variables, which makes unit testing difficult.
- ✗
Increased memory consumption for every instance
Why it's wrong here
Singletons usually reduce memory because only one instance exists.
About these practice questions
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official Python Institute exam blueprint
This PCPP2 practice question is part of Courseiva's free Python Institute certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCPP2 exam.