Write a function sum67 that takes a list as an input parameter and returns the sum of the numbers in the list, except ignore sections of numbers starting with a 6 and extending to the next 7 (every 6 will be followed by at least one 7). Return ( for no numbers. Examples: sum67([1, 2, 2]) + 5 sum67([1, 2, 2, 6, 99, 99, 7]) 5 sum67([1, 1, 6, 7,2]) + 4 sum67[1, 6, 2, 2, 7, 1, 6, 99, 99, 7] +2 sum67([1, 6, 2, 6, 2, 7, 1, 6, 99, 99, 7]) 2