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curriculum/challenges/english/blocks/learn-how-to-work-with-numbers-and-strings-by-implementing-the-luhn-algorithm/65687e457ab1c4cb8c3fe7c8.md

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--description--

Adjust the verify_card_number call such that if it returns True, print 'VALID!' to the console. Otherwise, print 'INVALID!'.

--hints--

You should have if verify_card_number(translated_card_number): within the main function.

js
({
    test: () => {
        const transformedCode = code.replace(/\r/g, "");
        const main = __helpers.python.getDef("\n" + transformedCode, "main");
        const { function_body } = main;
        
        const if_statement = __helpers.python.getBlock("\n" + function_body, "if verify_card_number(translated_card_number)");
        assert.exists(if_statement);
    }
})

You should have print('VALID!') within the if statement.

js
({
    test: () => {
        const transformedCode = code.replace(/\r/g, "");
        const if_statement = __helpers.python.getBlock("\n" + transformedCode, "if verify_card_number(translated_card_number)");
        const {block_body} = if_statement;

        assert.match(block_body, /print\(\s*('|")VALID!\1\s*\)/);
    }
})

You should have print('INVALID!') within the else clause.

js
({
    test: () => {
        const transformedCode = code.replace(/\r/g, "");
        const else_statement = __helpers.python.getBlock("\n" + transformedCode, "else");
        const {block_body} = else_statement;

        assert.match(block_body, /print\(\s*('|")INVALID!\1\s*\)/);
    }
})

--seed--

--seed-contents--

py
def verify_card_number(card_number):
    sum_of_odd_digits = 0
    card_number_reversed = card_number[::-1]
    odd_digits = card_number_reversed[::2]

    for digit in odd_digits:
        sum_of_odd_digits += int(digit)

    sum_of_even_digits = 0
    even_digits = card_number_reversed[1::2]
    for digit in even_digits:
        number = int(digit) * 2
        if number >= 10:
            number = (number // 10) + (number % 10)
        sum_of_even_digits += number
    total = sum_of_odd_digits + sum_of_even_digits
    print(total)
    return total % 10 == 0
--fcc-editable-region--
def main():
    card_number = '4111-1111-4555-1142'
    card_translation = str.maketrans({'-': '', ' ': ''})
    translated_card_number = card_number.translate(card_translation)

    verify_card_number(translated_card_number)
--fcc-editable-region--

main()