def get_permutations(arr):
    """
    Args:
     arr(list_int32)
    Returns:
     list_list_int32
    """
    # Write your code here.
    result = []
    def phelper(slate, arr):
        # base case
        if len(arr) == 0:
            result.append(slate[:])
            return
        # recursive case
        else:
            for i in range(len(arr)):
                slate.append(arr[i])
                phelper(slate, arr[:i]+arr[i+1:])
                slate.pop()
            return
    phelper([], arr)
    return result