How to save a nested dictionary with `save_npz`

[rqx110]

If i have a data struct like:

{
   "port1": {
                 "time": ["xxxx", "yyyy"],
                 "data": [0.0, 0.0]
                },
   "port2": {
                 "time": ["xxxx", "yyyy"],
                 "data": [0.0, 0.0]
                },
}

how to save it with save_npz?
can you give same sample codes? Thanks!