const sentence = 'The quick brown fox jumps over the lazy dog.';
console.log(sentence.toLowerCase());
// expected output: "the quick brown fox jumps over the lazy dog."
/[A-Z]/ : 'must contain one uppercase'
/([a-z])/ : 'must contain one lowercase'
/(d)/ : 'must contain one number'
/(W)/ : 'must contain one special character'