Implement a Multithreaded Map

Implement a thread-safe map data structure in a multithreaded environment. Design this data structure so that it can safely perform insert, delete, and lookup operations. Ensure it performs stably even in high concurrency scenarios. Provide the function interface and relevant test cases. The data size should support up to 10,000 different key-value operations. Example: # Example Input: put('key1', 'value1') put('key2', 'value2') get('key1') -> 'value1' delete('key2') get('key2') -> None Provide at least 5 different input test cases. Example Input put('key1', 'value1') get('key1') put('key2', 'value2') get('key2') delete('key1') get('key1')