How to get from POST request .getresponse()(json) specific thing("access_token": value)? (using import http.client)

Question

I get json as response as:

{"access_token":"QVQ6YmNlZjI0fdsfsFSZiLWE0OTgtZGUwMTJhMDdjMjYz","token_type":"Bearer","expires_in":7776000}

How do I write to a variable just one value from response?
Need "access_token" key value (= QVQ6YmNlZjI0fdsfsFSZiLWE0OTgtZGUwMTJhMDdjMjYz)?
Also should I better use import requests and if so, how this code would look in there?
Code: (New code with title fixed problem)

import http.client
import json

#Request Client Credential Grant (CCG) token
conn = http.client.HTTPSConnection("sandbox.handelsbanken.com")

payload = "client_id=45325132-fsafsa-saczx&grant_type=client_credentials&scope=AIS"

headers = {
    'Accept': "application/json",
    'Content-Type': "application/x-www-form-urlencoded",
    'content-type': "application/x-www-form-urlencoded",
    'accept': "application/json"
    }

conn.request("POST", "/openbanking/oauth2/token/1.0", payload, headers)

res = conn.getresponse()
data = res.read()
y = json.loads(data)

access_token = y.get("access_token", None) 

#print(data.decode("utf-8"))

Next problem is implementing it in new headers

payload = "{\"access\":\"ALL_ACCOUNTS\"}"

headers = { 'X-IBM-Client-Id': "REPLACE_THIS_VALUE", '
Authorization': "Bearer "+access_token, '
Country': "REPLACE_THIS_VALUE", '
TPP-Transaction-ID': "REPLACE_THIS_VALUE", '
TPP-Request-ID': "REPLACE_THIS_VALUE", '
content-type': "application/json", '
accept': "application/json" }

Do I do it like this?
I understood that I can't comprehend how do another thing with json..

{
  "accounts": [
    {
      "accountId": "ae57e780-6cf3-11e9-9c41-e957ce7d7d69",
      "iban": "SE5460000000000403333911",
      "bban": "403333911",
      "currency": "SEK",
      "accountType": "Allkortskonto",
      "bic": "HANDSESS",
      "clearingNumber": "6295",
      "ownerName": "Bo Bankkund",
      "_links": {
        "transactions": {
          "href": "https://sandbox.handelsbanken.com/openbanking/psd2/v2/accounts/ae57e780-6cf3-11e9-9c41-e957ce7d7d69/transactions"
        }
      }
    },
    {
      "accountId": "ae5835a0-6cf3-11e9-9c41-e957ce7d7d69",
      "iban": "SE8160000000000401975231",
      "bban": "401975231",
      "currency": "SEK",
      "accountType": "Allkonto Ung",
      "bic": "HANDSESS",
      "clearingNumber": "6295",
      "name": "Almas konto",
      "ownerName": "Alma Bankkund",
      "_links": {
        "transactions": {
          "href": "https://sandbox.handelsbanken.com/openbanking/psd2/v2/accounts/ae5835a0-6cf3-11e9-9c41-e957ce7d7d69/transactions"
        }
      }
    }
  ]
}

How to get first "accountId" key value in a variable?

Answer 1

1.How do I write to a variable just one value from response?:

data = res.read()
y = json.loads(data) #transforms "data" to json

access_token = y.get("access_token", None) #access "access_token" value and if there's no value makes it none with "None"

2. Next problem is implementing it in new headers:

headers = { 'X-IBM-Client-Id': "REPLACE_THIS_VALUE", '
Authorization': "Bearer "+access_token, '
Country': "REPLACE_THIS_VALUE", '
TPP-Transaction-ID': "REPLACE_THIS_VALUE", '
TPP-Request-ID': "REPLACE_THIS_VALUE", '
content-type': "application/json", '
accept': "application/json" }

3. How to get first "accountId" key value in a variable?

data = res.read()
y = json.loads(data)
accounts = y["accounts"][0] # saves in variable first accounts array elements
accountId = accounts["accountId"] #from accounts variable takes "accountId" value