function hasUsefulAccessibility(node) {
	switch (node.accessibility) {
		case "protected":
		case "private":
			return true;
		case "public":
			return !!node.parent.parent.superClass;
		default:
			return false;
	}
}
Checks whether a node's accessibility makes it not useless.
@param {ASTNode} node A method definition node.
@returns {boolean} `true` if the node has a useful accessibility.