Sending keypresses to a game, it doesn't work for arrow buttons

I'm trying to send keyboard inputs to a game, and after a lot of search I finally found a code that works:

# http://www.gamespp.com/directx/directInputKeyboardScanCodes.html

import ctypes
import time

SendInput = ctypes.windll.user32.SendInput

W = 0x11
A = 0x1E
S = 0x1F
D = 0x20
Z = 0x2C
X = 0x2D
Q = 0x10
UP = 0xC8
DOWN = 0xD0
LEFT = 0xCB
RIGHT = 0xCD
ENTER = 0x1C 

# C struct redefinitions 
PUL = ctypes.POINTER(ctypes.c_ulong)
class KeyBdInput(ctypes.Structure):
    _fields_ = [("wVk", ctypes.c_ushort),
                ("wScan", ctypes.c_ushort),
                ("dwFlags", ctypes.c_ulong),
                ("time", ctypes.c_ulong),
                ("dwExtraInfo", PUL)]

class HardwareInput(ctypes.Structure):
    _fields_ = [("uMsg", ctypes.c_ulong),
                ("wParamL", ctypes.c_short),
                ("wParamH", ctypes.c_ushort)]

class MouseInput(ctypes.Structure):
    _fields_ = [("dx", ctypes.c_long),
                ("dy", ctypes.c_long),
                ("mouseData", ctypes.c_ulong),
                ("dwFlags", ctypes.c_ulong),
                ("time",ctypes.c_ulong),
                ("dwExtraInfo", PUL)]

class Input_I(ctypes.Union):
    _fields_ = [("ki", KeyBdInput),
                 ("mi", MouseInput),
                 ("hi", HardwareInput)]

class Input(ctypes.Structure):
    _fields_ = [("type", ctypes.c_ulong),
                ("ii", Input_I)]

# Actuals Functions

def pressKey(hexKeyCode):
    extra = ctypes.c_ulong(0)
    ii_ = Input_I()
    ii_.ki = KeyBdInput( 0, hexKeyCode, 0x0008, 0, ctypes.pointer(extra) )
    x = Input( ctypes.c_ulong(1), ii_ )
    ctypes.windll.user32.SendInput(1, ctypes.pointer(x), ctypes.sizeof(x))

def releaseKey(hexKeyCode):
    extra = ctypes.c_ulong(0)
    ii_ = Input_I()
    ii_.ki = KeyBdInput( 0, hexKeyCode, 0x0008 | 0x0002, 0, 
ctypes.pointer(extra) )
    x = Input( ctypes.c_ulong(1), ii_ )
    ctypes.windll.user32.SendInput(1, ctypes.pointer(x), ctypes.sizeof(x))

if __name__ == '__main__':
    pressKey(0x11)
    time.sleep(1)
    releaseKey(0x11)
    time.sleep(1)

Here's how I adapted it in my program:

def press(key):
    num = KEYS[key] # Global dict which makes a mapping
                    # Of "W" to 0x11 for example
    pressKey(num)
    time.sleep(1)       
    releaseKey(num) 

While it does work for letters such as "Z, X, W, B, etc.." It doesn't seem to work for arrows (UP - DOWN - LEFT - RIGHT). The arrows do work in notepad but they do not work in the game. How can I modify this code so that it can work for arrow buttons as well?

The Numpad has arrow keys on 4, 6, 8, and 2. It's pressing those. Turn off Numpad Lock on your keyboard. I had the same issue and I feel pretty stupid now.