def _find_last(input_list, wanted):
    """Find the index of the last instance of a wanted element.

    Parameters
    ----------
    input_list : list
        A list to search through.
    wanted : str
        The element for which the last index is wanted.
    """

    # Run through the list, backwards
    for ind, elem in enumerate(reversed(input_list)):

        # If element is the wanted one, return index
        if elem == wanted:
            return len(input_list) - 1 - ind