karabiner elements - shift press alone as parenthesis

karabiner.json

//add these 2 rules in ~/.config/karabiner/karabiner.json under profiles/complex_modifications/rules
{
                        "description": "Change left_shift to left parens if alone.",
                        "manipulators": [
                            {
                                "from": {
                                    "key_code": "left_shift",
                                    "modifiers": {
                                        "optional": [
                                            "any"
                                        ]
                                    }
                                },
                                "to": [
                                    {
                                        "key_code": "left_shift"
                                    }
                                ],
                                "to_if_alone": [
                                    {
                                        "key_code": "9",
                                        "modifiers": ["left_shift"]
                                    }
                                ],
                                "type": "basic"
                            }
                        ]
                    },
                    {  "description": "Change right_shift to right parens if alone.",
                        "manipulators": [
                            {
                                "from": {
                                    "key_code": "right_shift",
                                    "modifiers": {
                                        "optional": [
                                            "any"
                                        ]
                                    }
                                },
                                "to": [
                                    {
                                        "key_code": "right_shift"
                                    }
                                ],
                                "to_if_alone": [
                                    {
                                        "key_code": "0",
                                        "modifiers": ["right_shift"]
                                    }
                                ],
                                "type": "basic"
                            }]
                    }