code: def close(self):
          
          try:
              # Purge last token from head node with <Close> message.
              sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
              sock.connect((self.server, self.port))
              self._hello(sock)
  
              comms.send_message(sock, ("<Close>" + self._get_token() + "</Close>").encode())
              reply = comms.recv_message(sock)
              ok, = struct.unpack('!I', reply)
              assert ok
              sock.close()
          except Exception as e:
              self._log_error(e)
          if self.client_socket:
              self.client_socket.close()
              self.client_socket = None
docs: gym api close