def unique(list1, list2):
    """Get the unique items that are in the first list but not in the second 
    list.
    NOTE: unique(l1,l2) is not always equal to unique(l2,l1)
    
    Args:
        list1 (list): A list of elements.
        list2 (list): A list of elements.
    
    Returns:
        list: A list with the unique elements.
    
    Examples:
        >>> unique([1,2,3], [2,3,4])
        [1]
        >>> unique([2,3,4], [1,2,3])
        [4]
    """
    return list(set(list1) - set(list2))