Finding specific words in JSON using python

I am writing automation script that parses a word document. I turn the keywords and their values into JSON object. But I can't get the specific values from there. I want to get applied voltage values from each and put them into a list.

Here is my JSON object: (just the beginning of it there are 19 test cases)

{
   "Test Case 1": [
      {
         "Test Case": "Test Case 1 : SENSOR_VCC Sinyal İşlemleri  ",
         "Test Step": "Test Step 1",
         "Sub_Tests": [
            {
               "Port": "J7-9",
               "Applied Voltage": "4",
               "Expected Result": 5.0,
               "Tolerance": 0.3
            },
            {
               "Port": "J7-9",
               "Applied Voltage": "3.3",
               "Expected Result": 4.125,
               "Tolerance": 0.3
            },
            {
               "Port": "J7-9",
               "Applied Voltage": "0",
               "Expected Result": 0.0,
               "Tolerance": 0.3
            }
         ]
      }
   ],
   "Test Case 2": [
      {
         "Test Case": "Test Case 2 : REF_0V Sinyal İşlemleri  ",
         "Test Step": "Test Step 1",
         "Sub_Tests": [
            {
               "Port": "J7-15",
               "Applied Voltage": "5",
               "Expected Result": 5.0,
               "Tolerance": 0.3
            },
            {
               "Port": "J7-15",
               "Applied Voltage": "3.3",
               "Expected Result": 3.3,
               "Tolerance": 0.3
            },
            {
               "Port": "J7-15",
               "Applied Voltage": "0",
               "Expected Result": 0.0,
               "Tolerance": 0.3
            }
         ]
      }
   ],
   "Test Case 3": [
      {
#.... so on

Here is my code: (I was successfull until I tried to have voltage_values list.)

        with open("signal_procedure.json", "r") as file:
            analogOut.procedure = json.load(file)
            print(type(analogOut.procedure))
        #Getting test cases
        listof_cases = []
        index = 0
        for index in analogOut.procedure.keys():
            listof_cases.insert(len(listof_cases), index)
        #getting values of the test case dictionary
        listof_content = []
        index = 0
        for index in analogOut.procedure.values():
            listof_content.insert(len(listof_content), index)

        index = 0
        x = 0
        voltage_values = []
        for x in listof_content:
            if "Applied Voltage" in x:
                voltage_values.index(len(voltage_values), x.values())
        print(voltage_values)

IIUC you can do:

dct = {
    "Test Case 1": [
        {
            "Test Case": "Test Case 1 : SENSOR_VCC Sinyal İşlemleri  ",
            "Test Step": "Test Step 1",
            "Sub_Tests": [
                {
                    "Port": "J7-9",
                    "Applied Voltage": "4",
                    "Expected Result": 5.0,
                    "Tolerance": 0.3,
                },
                {
                    "Port": "J7-9",
                    "Applied Voltage": "3.3",
                    "Expected Result": 4.125,
                    "Tolerance": 0.3,
                },
                {
                    "Port": "J7-9",
                    "Applied Voltage": "0",
                    "Expected Result": 0.0,
                    "Tolerance": 0.3,
                },
            ],
        }
    ],
    "Test Case 2": [
        {
            "Test Case": "Test Case 2 : REF_0V Sinyal İşlemleri  ",
            "Test Step": "Test Step 1",
            "Sub_Tests": [
                {
                    "Port": "J7-15",
                    "Applied Voltage": "5",
                    "Expected Result": 5.0,
                    "Tolerance": 0.3,
                },
                {
                    "Port": "J7-15",
                    "Applied Voltage": "3.3",
                    "Expected Result": 3.3,
                    "Tolerance": 0.3,
                },
                {
                    "Port": "J7-15",
                    "Applied Voltage": "0",
                    "Expected Result": 0.0,
                    "Tolerance": 0.3,
                },
            ],
        }
    ],
}

out = {}
for k, v in dct.items():
    out[k] = [[dd.get("Applied Voltage") for dd in d["Sub_Tests"]] for d in v]

print(out)

Prints:

{
"Test Case 1": [["4", "3.3", "0"]], 
"Test Case 2": [["5", "3.3", "0"]]
}