code: def recv(self, mac_addr=broadcast_addr, timeout=0):
          
          # recv on the broadcast address "00:..:00" will give you all packets (for promiscuous mode)
          if self.keep_listening:
              try:
                  return self.inq[str(mac_addr)].get(timeout=timeout)
              except Empty:
                  return ""
          else:
              self.log("is down.")
docs: read packet off the recv queue for a given address, optional timeout to block and wait for packet