def find(node, localname):
    """Find the first element under `node` with a matching localname.

    Args:
        node: An lxml etree Element object.
        localname: An XML localname for an element.

    Returns:
        An lxml etree Element object if found or None if not found.
    """
    xmltag = '{*}%s' % localname
    return node.find(xmltag)
