code: def send(self, packet, interfaces=None):
          
          interfaces = interfaces or self.interfaces  # default to all interfaces
          interfaces = interfaces if hasattr(interfaces, '__iter__') else [interfaces]
  
          for interface in interfaces:
              for f in self.filters:
                  packet = f.tx(packet, interface)  # run outgoing packet through the filters
              if packet:
                  # if not dropped, log the transmit and pass it to the interface's send method
                  # self.log("OUT     ", ("<"+",".join(i.name for i in interfaces)+">").ljust(30), packet.decode())
                  interface.send(packet)
docs: write packet to given interfaces, default is broadcast to all interfaces