Create a function that takes an array of strings and integers, and filters out the array so that it returns an array of integers only.
filter_array([1, 2, 3, "a", "b", 4]) ➞ [1, 2, 3, 4]
filter_array(["A", 0, "Edabit", 1729, "Ruby", "1729"]) ➞ [0, 1729]
filter_array(["Nothing", "here"]) ➞ []Don't overthink this one.