Why is an expression like ['a']['b'] an error instead of getting values from a nested dict?

I am trying to get the subscriber count from a youtube channel using the youtube api. However the repsonse sends a nested dict with more information than just the subscriber count. Here is the code I tried using to solve the problem

from googleapiclient.discovery import build

api_key = 'my_key'

youtube = build('youtube', 'v3', developerKey=api_key)

request = youtube.channels().list(
    part='statistics',
    forUsername='pewdiepie'
    )

response = dict(request.execute())

print(response)
print(['items']['statistics'])

However I come up with this error

list indices must be integers or slices, not str

Here is the response I get from the youtube api

{'kind': 'youtube#channelListResponse', 'etag': 'b1tpsekLNgax8TyB0hih1FujSL4', 'pageInfo': {'totalResults': 1, 'resultsPerPage': 5}, 'items': [{'kind': 'youtube#channel', 'etag': 'gdAP8rVq0n-1Bj2eyjvac-CrtdQ', 'id': 'UC-lHJZR3Gqxm24_Vd_AJ5Yw', 'statistics': {'viewCount': '28147953019', 'subscriberCount': '111000000', 'hiddenSubscriberCount': False, 'videoCount': '4459'}}]}

>Solution :

Change the last line in your code to:

for item in response['items']:
  print(item['statistics'])