Search by a particular node

Hello I was wondering if someone can help me with a problem i have encountered. I'm new to groovy scripting and I want to make an assert for the following json :
{"settings": {"bike_settings": [{
"drive_unit_id": "sndu20000011",
"bike_weight": 15,
"equipment_weight": 50,
"wheel_size": 50,
"name": "bike",
"wheel_size_correction_factor": 0,
"custom_assistance_levels": [
{
"max_torque": 30,
"point1": "0,1",
"point2": "2,30",
"point3": "3,40",
"point4": "4,50",
"point5": "8,0",
"level": 2
},
{
"max_torque": 30,
"point1": "0,1",
"point2": "2,10",
"point3": "3,40",
"point4": "3,5",
"point5": "8,0",
"level": 4
},
{
"max_torque": 30,
"point1": "0,1",
"point2": "2,30",
"point3": "3,40",
"point4": "3,5",
"point5": "8,0",
"level": 1
},
{
"max_torque": 29,
"point1": "0,1",
"point2": "2,30",
"point3": "3,40",
"point4": "4,50",
"point5": "8,0",
"level": 3
}
],
i want to verify that for level 4 the value for point4 is 3,5 but so far i could not store the node for level 4 and to verify that for that node the value for point 4 is 3,5
Does anyone know how to do this
thank you