Function concat

crates/vm/src/stdlib/_operator.rs:161–171

(a: PyObjectRef, b: PyObjectRef, vm: &VirtualMachine)

    #[pyfunction]
    fn concat(a: PyObjectRef, b: PyObjectRef, vm: &VirtualMachine) -> PyResult {
        // Best attempt at checking that a is sequence-like.
        if !a.class().has_attr(identifier!(vm, __getitem__))
            || a.fast_isinstance(vm.ctx.types.dict_type)
        {
            return Err(
                vm.new_type_error(format!("{} object can't be concatenated", a.class().name()))
            );
        }
        vm._add(&a, &b)
    }

    #[pyfunction]
    fn contains(a: PyObjectRef, b: PyObjectRef, vm: &VirtualMachine) -> PyResult<bool> {