def required_elements(element, *children):
    """Check element (``xml.etree.ElementTree.Element``) for required children, defined as XPath. Raise
    ``NotValidXmlException`` on error.

    :param element: ElementTree element
    :param children: list of XPaths to check
    :raises NotValidXmlException: if some child is missing
    """
    for child in children:
        if element.find(child) is None:
            raise NotValidXmlException(msg_err_missing_children(element.tag, *children))
Check element (``xml.etree.ElementTree.Element``) for required children, defined as XPath. Raise
    ``NotValidXmlException`` on error.

    :param element: ElementTree element
    :param children: list of XPaths to check
    :raises NotValidXmlException: if some child is missing