code: def _schedule_processing_blocks(self):
          
          LOG.info('Starting to Schedule Processing Blocks.')
          while True:
              time.sleep(0.5)
              if not self._queue:
                  continue
              if self._num_pbcs >= self._max_pbcs:
                  LOG.warning('Resource limit reached!')
                  continue
              _inspect = Inspect(app=APP)
              if self._queue and _inspect.active() is not None:
                  next_pb = self._queue[-1]
                  LOG.info('Considering %s for execution...', next_pb[2])
                  utc_now = datetime.datetime.utcnow()
                  time_in_queue = (utc_now -
                                   datetime_from_isoformat(next_pb[4]))
                  if time_in_queue.total_seconds() >= 10:
                      item = self._queue.get()
                      LOG.info('------------------------------------')
                      LOG.info('>>> Executing %s! <<<', item)
                      LOG.info('------------------------------------')
                      execute_processing_block.delay(item)
                      self._num_pbcs += 1
                  else:
                      LOG.info('Waiting for resources for %s', next_pb[2])
docs: Schedule Processing Blocks for execution.