def _search_index(items_list, item):
    """
    Give the index of an item in a list or return -1 if this item is not in the list

    :param items_list: list with one item or more
    :type items_list: list

    :param item: an item
    :type item: booleen, float, int, list, numpy.ndarray

    :return: the index of the item in the list, or -1
    :rtype: int
    """
    if (item in items_list) is True:
        return items_list.index(item)
    else:
        return -1