def _connToNode(self, conn):
        """
        Find the node to which a connection belongs.

        :param conn: connection object
        :type conn: TcpConnection
        :returns corresponding node or None if the node cannot be found
        :rtype Node or None
        """

        for node in self._connections:
            if self._connections[node] is conn:
                return node
        return None
Find the node to which a connection belongs.

        :param conn: connection object
        :type conn: TcpConnection
        :returns corresponding node or None if the node cannot be found
        :rtype Node or None