title: how to tell if a semaphore is full in python
body: <p>I have a bounded semaphore object that ensures my program doesn't download more than a certain number of files at a time. Each worker thread acquires the semaphore when it starts downloading and releases it when done. </p>
  
  <p>I have another thread that would like to run code when nothing is being downloaded. I would like a method for locking until the semaphore is completely available. How can I do this in Python?</p>