code: def make_shell_endpoint(topologyInfo, instance_id):
    
    # Format: container_<id>_<instance_id>
    pplan = topologyInfo["physical_plan"]
    stmgrId = pplan["instances"][instance_id]["stmgrId"]
    host = pplan["stmgrs"][stmgrId]["host"]
    shell_port = pplan["stmgrs"][stmgrId]["shell_port"]
    return "http://%s:%d" % (host, shell_port)
docs: Makes the http endpoint for the heron shell
    if shell port is present, otherwise returns None.