function set_attribute(element, key, value = '') {
	if (key.startsWith('xlink:')) {
		element.setAttributeNS('http://www.w3.org/1999/xlink', key, value);
		return;
	}
	return element.setAttribute(key, value);
}
@param {Element} element
@param {string} key
@param {string} value
@returns