/**
 * This function takes two sentences as input and returns a string that is a concatenation of the two sentences,
 * only if both sentences are at least 10 characters long. If not, it returns null.
 */
fun stringManipulation(sentence1: String, sentence2: String): String? {

    return if (sentence1.length >= 10 && sentence2.length >= 10) {
        sentence1 + sentence2
    } else {
        null
    }
}
/**
 * This function takes two sentences as input and returns a string that is a concatenation of the two sentences,
 * only if both sentences are at least 10 characters long. If not, it returns null.
 */
fun stringManipulation(sentence1: String, sentence2: String): String? {
/**
 * This function takes two sentences as input and returns a string that is a concatenation of the two sentences,
 * only if both sentences are at least 10 characters long. If not, it returns null.
 */
fun stringManipulation(sentence1: String, sentence2: String): String? {

    return if (sentence1.length >= 10 && sentence2.length >= 10) {
        sentence1 + sentence2
    } else {
        null
    }
}