def _get_first_tag_pos(base, tag, xmlkeys):
    """Returns a position were to add a subelement with the given tag.

    Args:
        base: The base node element. (lxml node)
        tag: The id to search for. (string)
        xmlkeys: The list of possible keys in the right order for xml (list strings)

    Returns:
        The int number of were to add the element with the tag.
    """
    listrest = xmlkeys[xmlkeys.index(tag):]
    counter = 0
    for node in base:
        if node.tag.replace('{http://www.rdml.org}', '') in listrest:
            return counter
        counter += 1
    return counter
