Write a function named remove_all that accepts as a parameter a list of strings along with an element value string, and returns a new list that is the same as the parameter list but with all occurrences of that string removed. For example, if a list named l contains ["a", "b", "c", "b", "b", "a", "b"], the call of remove_all(l, "b") should return ["a", "c", "a"].