Connect RPI with Bangle and send data

Thanks fanoush.
Re my understanding yes you are probably right.
To clarify I thought this line converted the python dictionary to a string:-

command = "X('+json.dumps(dict)+')/n"

and this line converted the json string to bytes:-

await client.write_gatt_char(UUID_NORDIC_TX,bytearray((c[0:20]),'utf-8') , True)
          c = c[20:]

I thought this would then be sent and my function would decode the bytes back to a json string:-

E.showMessage("Hello Code");

function X(dict) {
  msg = json.loads(dict.decode('utf-8'));
  
  E.showMessage(msg);

}

I dont now get the previous error, but the bleak library seems a little unreliable and gives a connection failure after a few attempts. However I am getting no response on the watch so I cant say its working yet.
I will try ascii and see if there's a difference,but I really need a more reliable bluetooth tranfer code. Hopefully the code comes out OK.
Many thanks for your help.
mike