Fix clippy lints

vm/src/obj/objtype.rs

@@ -47,7 +47,7 @@ impl PyValue for PyClass {
 
 #[pyimpl(flags(BASETYPE))]
 impl PyClassRef {
-    pub fn iter_mro<'a>(&'a self) -> impl Iterator<Item = &'a PyClassRef> + DoubleEndedIterator {
+    pub fn iter_mro(&self) -> impl Iterator<Item = &PyClassRef> + DoubleEndedIterator {
         std::iter::once(self).chain(self.mro.iter())
     }
 

vm/src/vm.rs

@@ -649,8 +649,8 @@ impl VirtualMachine {
                 descriptor,
                 vec![
                     descr,
-                    obj.unwrap_or(self.get_none()),
-                    cls.unwrap_or(self.get_none()),
+                    obj.unwrap_or_else(|| self.get_none()),
+                    cls.unwrap_or_else(|| self.get_none()),
                 ],
             ))
         } else {