Leonardo: Modifier key for Print Screen button

Here is code: Please try to compile the below code:

void setup() { // initialize
  Serial1.begin(9600);
  Serial.begin(9600);
  while (! Serial1);
  while (! Serial);

  Mouse.begin();  
  Keyboard.begin();
}

void loop() {
  
  if (Serial1.available() > 0) {
    char inChar = Serial1.read();
    
    switch (inChar) {   
        case '1':
        delay(1000); 
        Keyboard.press(KEY_LEFT_ALT);
        delay(100);
        Keyboard.press('f');
        delay(100);
        Keyboard.releaseAll();
        delay(100);
        Keyboard.press('o');
        delay(100);
        Keyboard.releaseAll();
        delay(500);
        //Here I want to do validation for open window. I need to take screen shot of open window by KeyBoard library.
        //If print screen would be implemented then code would be as below:
        
        Keyboard.press(KEY_PRNT_SCRN); //Yet Did not find modifier key for Print screen.
        delay(100);
        Keyboard.releaseAll();
        //open microsoft paint to store screen shot 
        Keyboard.press(KEY_LEFT_GUI) //window key
        Keyboard.press('r')
        delay(100);
        Keyboard.releaseAll();
        
        Keyboard.print("mspaint");
        delay(100);
        Keyboard.press(KEY_RETURN)
        delay(100);
        Keyboard.releaseAll();
        //Then Paste the screen shot by Cntrl+V and save the image.
        
        break;
        
        default:
        Serial.print("Default Case");
        
        
    } //switch end

  } //if end

}//void loop End