Python: Fix broken queries

python/ql/src/Variables/LoopVariableCapture/LoopVariableCaptureQuery.qll

@@ -3,8 +3,10 @@
 import python
 import semmle.python.dataflow.new.DataFlow
 
+final class FinalAstNode = AstNode;
+
 /** A looping construct. */
-abstract class Loop extends AstNode {
+abstract class Loop extends FinalAstNode {
   /**
    * Gets a loop variable of this loop.
    * For example, `x` and `y` in `for x,y in pairs: print(x+y)`
@@ -13,9 +15,9 @@ abstract class Loop extends AstNode {
 }
 
 /** A `for` loop. */
-private class ForLoop extends Loop, For {
+private class ForLoop extends Loop instanceof For {
   override Variable getALoopVariable() {
-    this.getTarget() = result.getAnAccess().getParentNode*() and
+    this.(For).getTarget() = result.getAnAccess().getParentNode*() and
     result.getScope() = this.getScope()
   }
 }