code: def add_peer(self, peer):
          
          if type(peer) == list:
              for i in peer:
                  check_url(i)
              self.PEERS.extend(peer)
          elif type(peer) == str:
              check_url(peer)
              self.PEERS.append(peer)
docs: Add a peer or multiple peers to the PEERS variable, takes a single string or a list.
  
          :param peer(list or string)