Write a method that has an input parameter called 'num' which is a non-negative integer. The method returns the sum of the digits in 'num', but this time it doesn't stop until that sum is a single digit. For example, funnyHatNumsAdvanced(99) returns 9 since 9+9=18. Look at the test data for further examples. Please note: NO STRING METHODS ARE ALLOWED in your solution! You MAY do this recursively but it is not required. Also, you MAY use a helper method.