class_docstr: Container for building and publishing ray docker images
code: def _get_image_version_tags(self) -> List[str]:
      branch = os.environ.get("BUILDKITE_BRANCH")
      sha_tag = os.environ["BUILDKITE_COMMIT"][:6]
      pr = os.environ.get("BUILDKITE_PULL_REQUEST", "false")
      if branch == "master":
          return [sha_tag, "nightly"]
  
      if branch and branch.startswith("releases/"):
          release_name = branch[len("releases/") :]
          return [f"{release_name}.{sha_tag}"]
  
      if pr != "false":
          return [f"pr-{pr}.{sha_tag}"]
  
      return [sha_tag]
  
file_path: ray/ci/ray_ci/docker_container.py
imports: import os
  from typing import List
  from ci.ray_ci.linux_container import LinuxContainer
  from ci.ray_ci.builder_container import DEFAULT_ARCHITECTURE, DEFAULT_PYTHON_VERSION
label_desc: Use image node_id 2 for calling the DockerContainer obj's underlying member method code with example usage: obj._get_image_version_tags() and returns: list, list, list, list