Write a function called remove_odds(xs) that deletes the elements that occur an odd number of times in the list xs, and leaves the elements that occur an even number of times alone. You should do this operation in place; your function should not return anything. You can assume that the elements in xs will be ints, floats, or strings. Of the built-in functions, you may only use len() and range(). Examples: remove odds([1,2,3,1,3,6,8,2,3]) -> [1,2,1,2] # in place, not returned remove_odds([4,5,5,2,7,2,6,7,7]) -> [5,5,2,2] # in place, not returned