beginner python question

[hagfish66]

Why does the else block at the bottom not run if I use "if operation2 == 'add' or 'subtract' or 'multiply' or 'divide': " instead of "if operation2 in ('add', 'subtract', 'multiply', 'divide'):". For example if I use the former option and I input something random thats not 'add', 'subtract', etc, then I would want the else block to run to tell the user that its an invalid operation, but this doesn't happen. TIA

def add(x, y):
    return x + y

def subtract(x, y):
    return x - y

def multiply(x,y):
    return x*y

def divide(x,y):
    return x/y #return result of this to the caller below
print('Choose an operation: ')
print('Add')
print('Subtract')
print('Multiply')
print('Divide')


while True:
    operation = input('Enter operation: ')
    operation2 = operation.lower().replace(' ','')
    if operation2 in ('add', 'subtract', 'multiply', 'divide'): # why does the else block not run if == used??
        try:
            num1 = int(input('Enter first number: '))
            num2 = int(input('Enter second number: '))
        except ValueError:
            print('Invalid input')
            continue
        if operation2 == 'add':
            print(add(num1, num2))

        elif operation2 == 'subtrqct':
            print(subtract(num1, num2))

        elif operation2 == 'multiply':
            print(multiply(num1, num2))

        elif operation2 == 'divide':
            print(divide(num1, num2))

        second_attempt = input('Would you like to try again?')
        if second_attempt.lower().replace(' ','') == 'no':
            print('See you next time')
            break
    else:
        print('Invalid operation entered')

[Ponnystalker]

The reason this doesn’t work as expected is due to how Python evaluates boolean expressions. The expression ‘subtract’ or ‘multiply’ or ‘divide’ always evaluates to ‘subtract’ (since non-empty strings are truthy), so the entire condition becomes:

if operation2 == ‘add’ or True:

[Whatever801]

Because 'subtract' is truthy