@classmethod
def from_xml(cls, node):
    """
        Construct a DesignRules instance from an EAGLE XML ``<designrules>``
        node.
        """
    name = node.attrib.get('name')
    descriptions = {}
    for desc_node in node.xpath('description'):
        lang = desc_node.attrib['language']
        descriptions[lang] = desc_node.text
    params = {}
    for param_node in node.xpath('param'):
        params[param_node.attrib['name']] = param_node.attrib['value']
    return cls(name=name, descriptions=descriptions, params=params)
