Create a function that takes two numbers as arguments 'num' and 'length' and returns an array of multiples of 'num' until the array length reaches 'length'. For example, if 'num' is 3 and 'length' is 5, you would return {3,6,9,12,15} because those are the first 5 multiples of 3. Look at the test data for more examples. Note: As preconditions you may assume that both 'num' and 'length' are positive.