Arduino UART via Python API

I am trying to interface boltiot with Arduino with UART protocol. And I programmed boltiot in python using API
The python code:

import json,time
from boltiot import Bolt

device = Bolt('xxx','xxx')

print(device.isOnline())

response = device.serialBegin(9600)

response2 = device.serialWrite("Hai")

print(response2)

print(response)

device.digitalWrite('0','LOW')

Arduino Code:

void setup() {
  Serial.begin(9600);
  Serial.print("1");
  Serial.setTimeout(50);
}

void loop() {
String x;
int i=0 ;

if(Serial.available()>0){
  Serial.println("hi");
  x = Serial.readString();
  Serial.println(x);
}

I am not getting any data to Arduino , is there anything I should add.

Hi @isaichakri,

When you run the python code, what is the output that you get? Could you share a screenshot of the output?