Left shift to left bracket '[' - is it possible?

[dnstarostin]

This is the code from 'Better shifting' element

"rules": [
{
"description": "Better Shifting: Parentheses on shift keys",
"manipulators": [
{
"from": {
"key_code": "left_shift"
},
"to": [
{
"key_code": "left_shift"
}
],
"to_if_alone": [
{
"key_code": "9",
"modifiers": [
"left_shift"
]
}
]

'9' stands for left parenthesis.

if I place 'open_bracket' there I get '{' not '['. Is there a way to call the square bracket?