code: def EnableFreeAPIKeyRateLimit(self):
      
      self._analyzer.hashes_per_batch = 4
      self._analyzer.wait_after_analysis = 60
      self._analysis_queue_timeout = self._analyzer.wait_after_analysis + 1
docs: Configures Rate limiting for queries to VirusTotal.
  
      The default rate limit for free VirusTotal API keys is 4 requests per
      minute.