Pyserial doesn't respond to Arduino - python-2.7

Question

I am trying to make USB serial communication between Arduino and Raspberry Pi 3. However, the Arduino IDE serial monitor outputs correct values, but it does not work finely in code using pyserial. The program is running normally, but there is no output on the output terminal.
Arduino code:
#include <DHT11.h>
int pin=2;
int pin1=4;
DHT11 dht11(pin);
DHT11 dht11(pin1);
void setup()
{
Serial.begin(9600);
while(!Serial) {
; //wait for serial port to connect. Needed for Leonardo only
}
}
void loop()
{
int sensorValue=analogRead(A0);
float outvoltage = sensorValue * (5.0 / 1023.0);
int Level = 6*outvoltage; //The level of wind speed is proportional to the output voltage.
int err1, err2;
float temp1, temp2, humi1, humi2;
if((err1=dht11.read(humi1, temp1))==0&&(err2=dht12.read(humi2, temp2))==0)
{
Serial.print(Level);
Serial.print(" ");
Serial.print(temp1);
Serial.print(" ");
Serial.print(humi1);
Serial.print(" ");
Serial.print(temp2);
Serial.print(" ");
Serial.print(humi2);
}
else
{
Serial.println();
Serial.print("Error No :");
Serial.print(err1);
Serial.print(err2);
Serial.println();
}
delay(1000); //delay for reread
}
Python code:
import serial
ser=serial.Serial("/dev/cu.usbmodemFD1411",9600)
while True:
print ser.readline()