Definition: In this task you will be given a list of numbers. You should remove any number that is not an integer (whole number). If every number is not an whole number then an empty list ("[]") should be returned. Otherwise, answer with the list of whole numbers separated by comma inside brackets.
Input: [-11.466, -21, 20.328, 20.846, 4.645, -23.691, -1.658, -2.996, -15]

[-21, -15]