message: Update TPUMirroredVariable assign_*_fn signatures
diff: @@ -983,7 +983,8 @@ class TPUMirroredVariable(trackable.Trackable):
  return self._read_variable_op()
  def assign_sub(self, *args, **kwargs):
  - def assign_sub_fn(var, delta, **kw):
  + def assign_sub_fn(var, delta, *ar, **kw):
  + del ar
  name = kw.pop("name", None)
  read_value = kw.pop("read_value", True)
  with self._handle_graph(var.handle):
  @@ -997,7 +998,8 @@ class TPUMirroredVariable(trackable.Trackable):
  return self._assign_func(f=assign_sub_fn, *args, **kwargs)
  def assign_add(self, *args, **kwargs):
  - def assign_add_fn(var, delta, **kw):
  + def assign_add_fn(var, delta, *ar, **kw):
  + del ar
  name = kw.pop("name", None)
  read_value = kw.pop("read_value", True)
  with self._handle_graph(var.handle):
  @@ -1011,7 +1013,8 @@ class TPUMirroredVariable(trackable.Trackable):
  return self._assign_func(f=assign_add_fn, *args, **kwargs)
  def assign(self, *args, **kwargs):
  - def assign_fn(var, value, **kw):
  + def assign_fn(var, value, *ar, **kw):
  + del ar
  name = kw.pop("name", None)
  read_value = kw.pop("read_value", True)
  with self._handle_graph(var.handle):
  