Global variable cannot be accessed inside a function?

[pvzzombs]

cowcowcow = 0
startX = 0
startY = 0
boardWidth = 20
boardHeight = 20
tileSize = 30
board = [[[1,2]]]

def markMine(x, y):
    print(cowcowcow)
    cowcowcow = cowcowcow + 1

def setup():
    size(startX + boardWidth * tileSize, startY + boardHeight * tileSize)
    stroke(255)
    if 'cowcowcow' in globals():
        print('cowcowcow')

def draw():
    background(0, 0, 0)

def keyTyped():
    if key == ' ':
        markMine(0, 0)

Output:

UnboundLocalError: local variable 'cowcowcow' referenced before assignment

The global variable of interest here is named cowcowcow. Every time the spacebar is hit, the markMine function will then be called. Suprisingly, it cannot access the global variable cowcowcow. But in the function setup, the string cowcowcow is printed in the console, this means that the function setup can access it, but the function markMine cannot?

[pvzzombs]

Processing version: 3.5.4 Python mode for processing 3 3063

[pvzzombs]

Closing this issue. The issue is not a bug. The solution is to use global <global_variable_name> inside a function to be able use it. Sorry about this. It is my bad.