message: Convert device_coordinates to tuples to retrieve correct device and task ordinals.
diff: @@ -189,12 +189,13 @@ class Topology(object):
  def cpu_device_name_at_coordinates(self, device_coordinates, job=None):
  """Returns the CPU device attached to a logical core."""
  return _tpu_host_device_name(
  - job, self._topology_tasks[device_coordinates])
  + job, self._topology_tasks[tuple(device_coordinates)])
  def tpu_device_name_at_coordinates(self, device_coordinates, job=None):
  """Returns the name of the TPU device assigned to a logical core."""
  - return _tpu_device_name(job, self._topology_tasks[device_coordinates],
  - self._topology_devices[device_coordinates])
  + return _tpu_device_name(job,
  + self._topology_tasks[tuple(device_coordinates)],
  + self._topology_devices[tuple(device_coordinates)])
  @property
  def num_tasks(self):
  