Method __getitem__

crates/stdlib/src/contextvars.rs:185–195

(
            &self,
            var: PyRef<ContextVar>,
            vm: &VirtualMachine,
        )

        }

        fn __getitem__(
            &self,
            var: PyRef<ContextVar>,
            vm: &VirtualMachine,
        ) -> PyResult<PyObjectRef> {
            let vars = self.borrow_vars();
            let item = vars
                .get(&*var)
                .ok_or_else(|| vm.new_key_error(var.into()))?;
            Ok(item.to_owned())
        }

        fn __len__(&self) -> usize {
            self.borrow_vars().len()