I have using ros1 - melodic and run in ubuntu 18.04 in Jetson-Nano I trying to access serial port of Jetson-Nano. But when i run with command "python3 serial_modules.py" then no error occurs but not access to serial port If I delete "import rospy" then everything is running fine

edit

Below is the code:

#!/usr/bin/env python3.6
import serial   #sudo apt-get install python3-serial
import time
import rospy

def initConnection(portNo, baudRate):
   try:
       ser = serial.Serial(portNo, baudRate)
       print("Device Connected")
       return ser
   except:
       print("Not Connected")

def sendData(se, data, name):
   myString = "$"
   for x in range(3):
       myString += (name[i] + ":" + str(data[i]) + "$")
   myString += "\r\n"
   try:
       se.write(myString.encode())
       #print(myString)
   except:
       print("Data Transmition Failed")

if __name__ == "__main__":
   ser = initConnection('/dev/ttyTHS1', 115200) # on jetson replace COM8 with /dev/ttyTHS1 coresponding
   while True:
       myString = "hello"
       ser.write(myString.encode())
       time.sleep(1)