'Exiting from a stage context will delete the stage directory unless:
- it was explicitly requested not to do so
- an exception has been raised
Args:
exc_type: exception type
exc_val: exception value
exc_tb: exception traceback
Returns:
Boolean'

def __exit__(self, exc_type, exc_val, exc_tb):

    if ((exc_type is None) and (not self.keep)):
        self.destroy()
    if (self._lock is not None):
        self._lock.release_write()
