Use get in store_cell

Author: palaviv

vm/src/scope.rs

@@ -114,8 +114,7 @@ impl NameProtocol for Scope {
 
     fn store_cell(&self, vm: &VirtualMachine, name: &str, value: PyObjectRef) {
         self.locals
-            .iter()
-            .nth(1)
+            .get(1)
             .expect("no outer scope for non-local")
             .set_item(name, value, vm)
             .unwrap();