Method count

crates/vm/src/stdlib/_collections.rs:109–117

(&self, obj: PyObjectRef, vm: &VirtualMachine)

        #[pymethod]
        fn count(&self, obj: PyObjectRef, vm: &VirtualMachine) -> PyResult<usize> {
            let start_state = self.state.load();
            let count = self.mut_count(vm, &obj)?;

            if start_state != self.state.load() {
                return Err(vm.new_runtime_error("deque mutated during iteration"));
            }
            Ok(count)
        }

        #[pymethod]
        fn extend(&self, iter: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {