* Returns the value of [block] if `this` is true, returns `null` otherwise.
*/
fun <R> Boolean.ifTrue(block: () -> R): R? = if (this) block() else null
+
+/**
+ * Returns the value of [block] if `this` is false, returns `null` otherwise.
+ */
+fun <R> Boolean.ifFalse(block: () -> R): R? = if (!this) block() else null