Python win32api - Cannot release CTRL key

I'm using a script I found here for simulating key presses:

from win32api import keybd_event
import time
import random


Combs = {
'A': [
    'SHIFT',
    'a'],
'B': [
    'SHIFT',
    'b'],
'C': [
    'SHIFT',
    'c'],
'D': [
    'SHIFT',
    'd'],
'E': [
    'SHIFT',
    'e'],
'F': [
    'SHIFT',
    'f'],
'G': [
    'SHIFT',
    'g'],
'H': [
    'SHIFT',
    'h'],
'I': [
    'SHIFT',
    'i'],
'J': [
    'SHIFT',
    'j'],
'K': [
    'SHIFT',
    'k'],
'L': [
    'SHIFT',
    'l'],
'M': [
    'SHIFT',
    'm'],
'N': [
    'SHIFT',
    'n'],
'O': [
    'SHIFT',
    'o'],
'P': [
    'SHIFT',
    'p'],
'R': [
    'SHIFT',
    'r'],
'S': [
    'SHIFT',
    's'],
'T': [
    'SHIFT',
    't'],
'U': [
    'SHIFT',
    'u'],
'W': [
    'SHIFT',
    'w'],
'X': [
    'SHIFT',
    'x'],
'Y': [
    'SHIFT',
    'y'],
'Z': [
    'SHIFT',
    'z'],
'V': [
    'SHIFT',
    'v'],
'Q': [
    'SHIFT',
    'q'],
'?': [
    'SHIFT',
    '/'],
'>': [
    'SHIFT',
    '.'],
'<': [
    'SHIFT',
    ','],
'"': [
    'SHIFT',
    "'"],
':': [
    'SHIFT',
    ';'],
'|': [
    'SHIFT',
    '\\'],
'}': [
    'SHIFT',
    ']'],
'{': [
    'SHIFT',
    '['],
'+': [
    'SHIFT',
    '='],
'_': [
    'SHIFT',
    '-'],
'!': [
    'SHIFT',
    '1'],
'@': [
    'SHIFT',
    '2'],
'#': [
    'SHIFT',
    '3'],
'$': [
    'SHIFT',
    '4'],
'%': [
    'SHIFT',
    '5'],
'^': [
    'SHIFT',
    '6'],
'&': [
    'SHIFT',
    'v'],
'*': [
    'SHIFT',
    '8'],
'(': [
    'SHIFT',
    '9'],
')': [
    'SHIFT',
    '0'] }
Base = {
'0': 48,
'1': 49,
'2': 50,
'3': 51,
'4': 52,
'5': 53,
'6': 54,
'7': 55,
'8': 56,
'9': 57,
'a': 65,
'b': 66,
'c': 67,
'd': 68,
'e': 69,
'f': 70,
'g': 71,
'h': 72,
'i': 73,
'j': 74,
'k': 75,
'l': 76,
'm': 77,
'n': 78,
'o': 79,
'p': 80,
'q': 81,
'r': 82,
's': 83,
't': 84,
'u': 85,
'v': 86,
'w': 87,
'x': 88,
'y': 89,
'z': 90,
'.': 190,
'-': 189,
',': 188,
'=': 187,
'/': 191,
';': 186,
'[': 219,
']': 221,
'\\': 220,
"'": 222,
'ALT': 18,
'TAB': 9,
'CAPSLOCK': 20,
'ENTER': 13,
'BS': 8,
'CTRL': 17,
'ESC': 27,
' ': 32,
'END': 35,
'DOWN': 40,
'LEFT': 37,
'UP': 38,
'RIGHT': 39,
'SELECT': 41,
'PRINTSCR': 44,
'INS': 45,
'DEL': 46,
'LWIN': 91,
'RWIN': 92,
'LSHIFT': 160,
'SHIFT': 161,
'LCTRL': 162,
'RCTRL': 163,
'VOLUP': 175,
'DOLDOWN': 174,
'NUMLOCK': 144,
'SCROLL': 145 }

def KeyUp(Key):
    keybd_event(Key, 0, 2, 0)


def KeyDown(Key):
    keybd_event(Key, 0, 1, 0)


def Press(Key, speed=1):
    rest_time = 0.05/speed
if Key in Base:
    Key = Base[Key]
    KeyDown(Key)
    time.sleep(rest_time)
    KeyUp(Key)
    return True
if Key in Combs:
    KeyDown(Base[Combs[Key][0]])
    time.sleep(rest_time)
    KeyDown(Base[Combs[Key][1]])
    time.sleep(rest_time)
    KeyUp(Base[Combs[Key][1]])
    time.sleep(rest_time)
    KeyUp(Base[Combs[Key][0]])
    return True
return False



def Write(Str, speed = 1):
    for s in Str:
        Press(s, speed)
        time.sleep((0.1 + random.random()/10.0) / float(speed))

I added a to the code a simple script that simulate CTRL+V (paste) method.

def Ctrlv(speed=1):
    rest_time = 0.05/speed
    KeyDown(17) #17 = CTRL
    time.sleep(rest_time)
    KeyDown(86) #86 = V
    KeyUp(17)
    KeyUp(86)

The code runs smoothly and the Ctrlv method paste correctly the clipboard text. The problem is that, after running the script, the CTRL key is still pressed and is not released by the KeyUp event.

Thank you guys.