Keyboard not found even though I'm including Keyboard.h - c++

Question

I want to make a simple program to put on my Arduino/Genuino (Sunfounder) Uno board that when plugged in, it invokes the Keyboard.print() function. When I compile my program to do that, it says that I'm not including Keyboard.h even though I actually am at the beginning of my program.
My code:
#include <Keyboard.h>
void setup() {
Keyboard.begin();
Keyboard.print("Hello, world!");
Keyboard.end();
}
void loop() {
}
When I compile the code, I get this error:
KeyboardMessage:4:3: error: 'Keyboard' not found. Does your sketch include the line '#include <Keyboard.h>'?
I checked my libraries file in the Arduino sketch editor file and Keyboard.h is there.
Any help is appreciated.

Answer 1

Arduino/Genuino Uno does not support Keyboard. You can see it in hardware/ardunino/avr/libraries/HID/HID.h. This file is included from Keyboard.h and contains #if defined(USBCON). But USBCON is not defined for Arduino/Genuino Uno. You need to use another board for Keyboard.h
Following controllers support it:
ATmega32U6
ATmega8U2
ATmega16U2
ATmega16U4
ATmega32U2
ATmega32U4
and some ATxxUSBxx
Arduino/Genuino Uno uses ATmega32U8.

Answer 2

You know what you don't require the 32u4 now, I got a solution to use keyboard and mouse through any Arduino.
All you have to do is something like this:
Serial.println("pressA")
On the Arduino
Head to a python script and do this:
import serial
import pyautogui
Arduino_Serial = serial.Serial('COM5', 9600)
while 1:
incoming_data = str(Arduino_Serial.readline())
print(incoming_data)
if 'pressA' in incoming_data:
pyautogui.press('a')
incoming_data = ""