code: def copy_between_containers(source_name, source_path, dest_name, dest_path):
      
      if not container_path_exists(source_name, source_path):
          raise RuntimeError('ERROR: Path {} does not exist inside container {}.'.format(source_path, source_name))
      temp_path = os.path.join(tempfile.mkdtemp(), str(uuid.uuid1()))
      with _cleanup_path(temp_path):
          copy_to_local(temp_path, source_name, source_path, demote=False)
          copy_from_local(temp_path, dest_name, dest_path, demote=False)
docs: Copy a file from the source container to an intermediate staging
      area on the local filesystem, then from that staging area to the
      destination container.
  
      These moves take place without demotion for two reasons:
        1. There should be no permissions vulnerabilities with copying
           between containers because it is assumed the non-privileged
           user has full access to all Dusty containers.
        2. The temp dir created by mkdtemp is owned by the owner of the
           Dusty daemon process, so if we demoted our moves to/from that location
           they would encounter permission errors.