How can we retrieve the cost of child tenancies using the OCI Python SDK and the Usage API?

How can we retrieve the costs of child tenancies using the OCI Python SDK and the Usage API.
Suppose I have four child tenancies, each associated with a single parent tenancy. I need to fetch the costs of those child tenancies with parent tenancies using Usage API calls.
@adizohar, can you guide me on how to achieve this?.

import oci

config = oci.config.from_file()
tenant_id = config['tenancy']
time_usage_started = "2024-04-01T00:00:00Z"
time_usage_ended = "2024-04-21T00:00:00Z"
lis=[]
usage_client = oci.usage_api.UsageapiClient(config,timeout=(10,3000))

requestSummarizedUsagesDetails = oci.usage_api.models.RequestSummarizedUsagesDetails(
    tenant_id=tenant_id,
    granularity='DAILY',
    query_type='USAGE',
    group_by=[ 'resourceId','service','compartmentName'],
    time_usage_started=time_usage_started,
    time_usage_ended=time_usage_ended,
    compartment_depth=2
)
# CUSTOM_RETRY_STRATEGY = RetryStrategyBuilder().add_max_attempts(max_attempts=8) \
#     .add_total_elapsed_time(total_elapsed_time_seconds=25000) \
#     .add_service_error_check(service_error_retry_config=retry_checkers.RETRYABLE_STATUSES_AND_CODES,
#                              service_error_retry_on_any_5xx=True) \
#     .get_retry_strategy()

# Retrieve summarized usage data
request_summarized_usages = usage_client.request_summarized_usages(
    requestSummarizedUsagesDetails,
    retry_strategy=oci.retry.DEFAULT_RETRY_STRATEGY
)

for item in request_summarized_usages.data.items:
    print(len(item.resource_id))

The issue contains a Python example using oci.usage_api.UsageapiClient and request_summarized_usages, but names no repository file or test. Start by reviewing the Usage API request and tenancy parameters shown in the example. Done would require a clear, verified explanation or documentation of how to retrieve child-tenancy costs from the parent tenancy.