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why i get the following error 'QTR_NO_EMITTER_PIN' was not declared in this scope?

here is my code:

#include <PololuQTRSensors.h>

#define NUM_SENSORS   1     // number of sensors used
#define TIMEOUT       2500  // waits for 2500 us for sensor outputs to go low
#define DETECT_LEVEL  150   // Sensor needs to change this amount for detection
#define TRIGGER_COUNT 10    // Wait n successive readings valid detection

// Create instance of sensors. We are only using one sensor connected to pin 12
PololuQTRSensorsRC qtrrc((unsigned char[]){12}, NUM_SENSORS,TIMEOUT,QTR_NO_EMITTER_PIN);
unsigned int sensorValues[NUM_SENSORS];
unsigned int sensorValuesBase[NUM_SENSORS];
unsigned int detect_count[NUM_SENSORS];    // Number of successive times sensor
                                           // has detected a drop in value. If
                                           // this is greater than trigger_count
                                           // then white line detected
// Setup pins for SN754410 Motor chip

int lf = 6;      // Left motor Forward
int lr = 5;      // Left motor Reverse
int rf = 11;     // Right motor Forward
int rr = 10;     // Right motor Reverse


int led = 3;    // LED and resistor across pins 2 and 3
int led_gnd = 2;

unsigned char line_detect=1;
unsigned char do_turn=0;

void setup()  {
  pinMode(led, OUTPUT);
  pinMode(led_gnd, OUTPUT);  
  digitalWrite(led_gnd, LOW);    // LED ground
 
  pinMode(13, OUTPUT);
  digitalWrite(13, HIGH);        // turn on Sensor
  //Read and store the baseline values
  qtrrc.read(sensorValues); 
  sensorValuesBase[0] = sensorValues[0];   
}

void loop()  {
 
  if(line_detect==1){  
    // Line Detect is enabled
    qtrrc.read(sensorValues);
    if(sensorValues[0] < (sensorValuesBase[0]- DETECT_LEVEL)) {
      // Detected drop on value - brighter object detected
      detect_count[0]++;   // incerment count
      if(detect_count[0] >= TRIGGER_COUNT) {
        // White Line detected
        detect_count[0]=0;          // Reset count
        do_turn=1;                  // Start the turn
        digitalWrite(led, HIGH);    // turn on LED     
        line_detect=0;              // Turn off detection until turn complete
     
        // Come to s stop
        analogWrite(lf, 0);        
        analogWrite(rf, 0);
        analogWrite(lr, 0);        
        analogWrite(rr, 0);     
        delay(200);     
      } 
    }
    else {
      detect_count[0]=0;
    } 

  }

  if(do_turn==1){
    //Turn right a bit to avoid obstacle
    analogWrite(lr, 0);    
    analogWrite(rf, 0);
    analogWrite(lf, 200);
    analogWrite(rr, 200);      
    delay(500);                // Turn for half a second
    line_detect=1;             // turn line_detect back on
    do_turn=0;                 // turn off
    digitalWrite(led, LOW);    // turn off Led
  }
  else {
    // go forward until we detect something
    // Forward
    analogWrite(lr, 0);        
    analogWrite(rr, 0);
    analogWrite(lf, 250);        
    analogWrite(rf, 250);    
  }

}


i add the library and it appear in sketch import library?

...because you haven't defined the pin

QTR_NO_EMITTER_PIN

?