arduino nano keyboard.h problem

Arduino: 1.6.13 (Windows 7), Board: “Arduino Nano, ATmega328”

In file included from C:\Program Files\Arduino\examples\09.USB\Keyboard\KeyboardMessage\KeyboardMessage.ino:23:0:

C:\Program Files\Arduino\libraries\Keyboard\src/Keyboard.h:29:2: warning: #warning “Using legacy HID core (non pluggable)” [-Wcpp]

#warning “Using legacy HID core (non pluggable)”

^

C:\Program Files\Arduino\examples\09.USB\Keyboard\KeyboardMessage\KeyboardMessage.ino: In function ‘void setup()’:

KeyboardMessage:33: error: ‘Keyboard’ not found. Does your sketch include the line ‘#include <Keyboard.h>’?
Keyboard.begin();

^

C:\Program Files\Arduino\examples\09.USB\Keyboard\KeyboardMessage\KeyboardMessage.ino: In function ‘void loop()’:

KeyboardMessage:46: error: ‘Keyboard’ not found. Does your sketch include the line ‘#include <Keyboard.h>’?
Keyboard.print("You pressed the button ");

^

exit status 1
‘Keyboard’ not found. Does your sketch include the line ‘#include <Keyboard.h>’?

This report would have more information with
“Show verbose output during compilation”
option enabled in File → Preferences.

" i don’t understand why it is happening when compiling the inbuilt examples or any program related to keyboard.h"

Try "Keyboard" with a lower case "k".

Isn't the keyboard library for e.g. 32U4 based boards? The nano uses a 328 micro.

Might be totally wrong.