in opentelemetry-resourcedetector-gcp/src/opentelemetry/resourcedetector/gcp_resource_detector/_gae.py [0:0]
def standard_availability_zone() -> str:
"""The zone the app engine service is running in.
Check that ``on_app_engine_standard()`` is true before calling this, or it may throw exceptions.
"""
zone = _metadata.get_metadata()["instance"]["zone"]
# zone is of the form "projects/233510669999/zones/us15"
return zone[zone.rfind("/") + 1 :]