​import serial
#COM port number, BaudRate, timeout, parity, rtscts, stopbits, xonxoff=0

#Open serial port

ser = serial.Serial('COM4', 9600, timeout=0,parity='N', rtscts=1,stopbits=1,xonxoff=0 ) 
#Send your device/instrument command inside write function 

ser.write(b'hello')    

#Read serial outputs

line = ser.read()
line = ser.readline()
print(line)

​# check which port was really used
print(ser.name)        

# close port
ser.close()