Python: Modernise tornado library

python/ql/src/semmle/python/web/tornado/Tornado.qll

@@ -3,26 +3,25 @@ import python
 import semmle.python.security.TaintTracking
 import semmle.python.web.Http
 
-private ClassObject theTornadoRequestHandlerClass() {
-    result = ModuleObject::named("tornado.web").attr("RequestHandler")
+private ClassValue theTornadoRequestHandlerClass() {
+    result = Value::named("tornado.web.RequestHandler")
 }
 
-ClassObject aTornadoRequestHandlerClass() {
-    result.getASuperType() = theTornadoRequestHandlerClass()
+ClassValue aTornadoRequestHandlerClass() {
+    result.getABaseType+() = theTornadoRequestHandlerClass()
 }
 
-/** Holds if `node` is likely to refer to an instance of a tornado 
+/** Holds if `node` is likely to refer to an instance of a tornado
  * `RequestHandler` class.
  */
-
 predicate isTornadoRequestHandlerInstance(ControlFlowNode node) {
-    node.refersTo(_, aTornadoRequestHandlerClass(), _)
+    node.pointsTo().getClass() = aTornadoRequestHandlerClass()
     or
     /* In some cases, the points-to analysis won't capture all instances we care
-     * about. For these, we use the following syntactic check. First, that 
-     * `node` appears inside a method of a subclass of 
+     * about. For these, we use the following syntactic check. First, that
+     * `node` appears inside a method of a subclass of
      * `tornado.web.RequestHandler`:*/
-    node.getScope().getEnclosingScope().(Class).getClassObject() = aTornadoRequestHandlerClass() and
+    node.getScope().getEnclosingScope() = aTornadoRequestHandlerClass().getScope() and
     /* Secondly, that `node` refers to the `self` argument: */
     node.isLoad() and node.(NameNode).isSelf()
 }