Associates a route table with a specific subnet.

        :type route_table_id: str
        :param route_table_id: The ID of the route table to associate.

        :type subnet_id: str
        :param subnet_id: The ID of the subnet to associate with.

        :rtype: str
        :return: The ID of the association created

def associate_route_table(self, route_table_id, subnet_id):
        """
        Associates a route table with a specific subnet.

        :type route_table_id: str
        :param route_table_id: The ID of the route table to associate.

        :type subnet_id: str
        :param subnet_id: The ID of the subnet to associate with.

        :rtype: str
        :return: The ID of the association created
        """
        params = {
            'RouteTableId': route_table_id,
            'SubnetId': subnet_id
        }

        result = self.get_object('AssociateRouteTable', params, ResultSet)
        return result.associationId