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Thread-Safe Singleton Implementation
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Thread-Safe Singleton Implementation

HardPython

Problem

Write a thread-safe implementation of a singleton class.

Implement lazy construction so concurrent callers always receive the same fully initialized object. The grading function accepts a positive thread count and returns True only when all concurrent and repeated accesses share one initialized instance.

Input and Output

Implement def verify_singleton(thread_count):. The input is an integer, and the function must return a boolean.

Constraints

  • 1 <= thread_count <= 256
  • The singleton must be created lazily
  • All callers must receive the same object
  • Initialization must execute exactly once
  • Use only Python standard-library functionality

Function Signature

def verify_singleton(thread_count):
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