def _get_args_mapping_host_path_to_container(host_path, container_path=None):
  """Get arguments to docker run that will map |host_path| a path on the host to
  a path in the container. If |container_path| is specified, that path is mapped
  to. If not, then |host_path| is mapped to itself in the container."""
  # WARNING: Do not use this function when running in production (and
  # --volumes-from) is used for mapping volumes. It will break production.
  container_path = host_path if container_path is None else container_path
  return ['-v', f'{host_path}:{container_path}']