Google Ads API - How to fetch data with MCC (manager account)

I am trying to fetch campaigns' reports from Google Ads API. But, getting an error when trying to fetch data with MCC:

Code:

  import sys,os   from google.ads.google_ads.client import GoogleAdsClient   from google.ads.google_ads.errors import GoogleAdsException   def get_data(client, customer_id):     ga_service = client.get_service("GoogleAdsService", version="v6")     query = """         SELECT           campaign.name,           campaign.status,           segments.device,           metrics.impressions,           metrics.clicks,           metrics.ctr,           metrics.average_cpc,           metrics.cost_micros         FROM campaign         WHERE segments.date DURING LAST_30_DAYS         """     # Issues a search request using streaming.     response = ga_service.search_stream(customer_id, query=query)     try:         for batch in response:             for row in batch.results:                 print(                     row                 )     except GoogleAdsException as ex:         print(             f'Request with ID "{ex.request_id}" failed with status '             f'"{ex.error.code().name}" and includes the following errors:'         )         for error in ex.failure.errors:             print(f'\tError with message "{error.message}".')             if error.location:                 for field_path_element in error.location.field_path_elements:                     print(f"\t\tOn field: {field_path_element.field_name}")         sys.exit(1)     if __name__ == "__main__":         # get client object with oauth2         credentials = {'developer_token': "xxxxxxxxxxxxxxx",             'refresh_token': "xxxxxxxxxxxxxxxx",             'client_id': "xxxxxxxxxxxxxxx",             'client_secret': "xxxxxxxxxxxxxxxx"                        }         google_ads_client = GoogleAdsClient.load_from_dict(credentials)              get_data(google_ads_client, 'xxxxxxxxx') 

Wehn Running the code with MCC client ID:

get_data(google_ads_client, 'MANAGER(MCC)_CLIENT_ID') 

I'm Getting Error_1:

Request made: ClientCustomerId: xxxxxxxxx, Host: googleads.googleapis.com:443, Method: /google.ads.googleads.v6.services.GoogleAdsService/SearchStream, RequestId: xxxxxxxxxx, IsFault: True, FaultMessage: Metrics cannot be requested for a manager account. To retrieve metrics, issue separate requests against each client account under the manager account.

I assumed, the solution would be to set a different ClientCustomerId of the account itself, not MCC. So I did, and run the code again with the client id of the direct account, and, got another error:

Wehn Running the code with Account client ID:

get_data(google_ads_client, 'ACCOUNT_CLIENT_ID') 

I'm Getting Error_2:

Request made: ClientCustomerId: xxxxxxx, Host: googleads.googleapis.com:443, Method: /google.ads.googleads.v6.services.GoogleAdsService/SearchStream, RequestId: xxxxxxxxxx, IsFault: True, FaultMessage: User doesn't have permission to access customer. Note: If you're accessing a client customer, the manager's customer id must be set in the 'login-customer-id' header. See https://developers.google.com/google-ads/api/docs/concepts/call-structure#cid

That error essentially says to insert the manager's client id, which I already did and got error_1 (!).

What am I missing here?