Python 3 OR statements within an IF not working? [duplicate]

This question already has an answer here:

• How do I test multiple variables against a value? 14 answers

if dirInput == ("up" or "Up" or "UP" or "u"): #up
    moveX = 0
    moveY = -1

I have this for all 4 directions. typing "up" works fine and moves the player up. same for all 4 directions. But, when I use the alternative ones like "Up" or "UP" or "u" they are unreliable. They'll either sometimes not work but othertimes work or down instead of up or whatever,.idk what's happening because it's a basic IF statement with basic ORs. Anyway, here's the entire code to look at if you need more context:

import os #o used for clear screen

width = input("Please enter grid width:") #grid width (string?)
width = int(width) #make integer
height = input("Please enter grid height:") #grid height (string?)
height = int(height) #make integer
grid = [["o" for x in range(width)] for y in range(height)] #initialize 2D grid matrix
playerX = int(round((width-1.25)/2)) #player X coordinate (center)
playerY = int(round((height-1.25)/2)) #player Y coordinate (center)
moveX = 0 #movement
moveY = 0 #movement
icon = ["o", "x"] #icons: grid(0), player(1)

def initializeGrid(): #create grid function
    for y in range(height): #for each row
        for x in range(width): #for each point
            grid[x][y] = "o" #assign "o" for each point

def drawGrid(): #draw grid function
    os.system('cls') #clear screen
    drawObjects() #draw objects and players
    gridRow = ["" for x in range(width)] #initialize 1D grid row matrix
    for y in range(height): #for each row
        for x in range(width): #for each point
            gridRow[y] += (str(grid[x][y]) + " ") #add all points in a row to grid row
        print(gridRow[y]) #print each row, for each collumn

def drawObjects(): #draw objects and players
    grid[playerX][playerY] = icon[1] #draw player icon

def move(): #movement
    global playerX #import playerX to function
    global playerY #import playerY to function
    grid[playerX][playerY] = "o" #remove player "x"
    playerX += moveX #update player X coordinate
    playerY += moveY #update player Y coordinate
    #don't go off edges
    if playerX < 0:
        playerX = 0
    if playerX >= width:
        playerX = width-1
    if playerY < 0:
        playerY = 0
    if playerY >= height:
        playerY = height-1
    drawGrid()
    step()

def step(): #loop through steps
    global moveX #import moveX
    global moveY #import moveY
    dirInput = "up"
    dirInput = input("Please type a direction to move:") #ask for direction input
    if dirInput == ("up" or "Up" or "UP" or "u"): #up
        moveX = 0
        moveY = -1
    elif dirInput == ("down" or "Down" or "DOWN" or "d"): #down
        moveX = 0
        moveY = 1
    elif dirInput == ("left" or "Left" or "LEFT" or "l"): #left
        moveX = -1
        moveY = 0
    elif dirInput == ("right" or "Right" or "RIGHT" or "r"): #right
        moveX = 1
        moveY = 0
    else:
        print("Incorrect directional input.")
        print("Please type: 'up', 'down', 'left', or 'right'.")
    move() #movement decided, now move

initializeGrid() #initialize the grid
drawGrid() #draw the grid
step() #repeat movement and grid drawing`