The Python Critical Sections part of the document describes how threads can only hold a single lock at a time to avoid deadlocks, where existing locks are released when a new lock is acquired.
If multiple locks are taken to ensure mutual consistency across multiple resources, is it possible that a second thread can acquire a released lock and make changes that are inconsistent with the work performed by the first thread? At first glance, this has the potential to violate program correctness in a multithreaded environment.