code: def test_regions():
      backend = hl.current_backend()
      assert isinstance(backend, ServiceBackend)
      old_regions = backend.regions
      CLOUD = os.environ["HAIL_CLOUD"]
      try:
          if CLOUD == "gcp":
              backend.regions = ["us-east1"]
          else:
              assert CLOUD == "azure"
              backend.regions = ["eastus"]
          hl.utils.range_table(1, 1).to_pandas()
      finally:
          backend.regions = old_regions
  
file_path: hail/hail/python/test/hail/backend/test_service_backend.py
imports: import os
  import hail
  from ..helpers import skip_unless_service_backend, test_timeout, qobtest
  from hail.backend.service_backend import ServiceBackend
label_desc: Use image node_id 5 for calling a global function with example usage: test_regions() without return types