Merges items into a list, appends ignoring duplicates but retaining the original order. This modifies the list and
    does not return anything.

    :param merged_list: List to append de-duplicated items to.
    :type merged_list: list
    :param items: Items to merge into the list.
    :type items: collections.Iterable

def merge_list(merged_list, items):
    """
    Merges items into a list, appends ignoring duplicates but retaining the original order. This modifies the list and
    does not return anything.

    :param merged_list: List to append de-duplicated items to.
    :type merged_list: list
    :param items: Items to merge into the list.
    :type items: collections.Iterable
    """
    if not items:
        return
    merged_set = set(merged_list)
    merged_add = merged_set.add
    merged_list.extend(item
                       for item in items
                       if item not in merged_set and not merged_add(item))