'tf.name_scope(self._scope)' what is the use of this one?

[yezhengli-Mr9]

Colocation Debug Info:
Colocation group had the following types and devices:
StridedSliceAssign: GPU CPU
RefSwitch: GPU CPU
Switch: GPU CPU
Assign: CPU
Identity: GPU CPU
VariableV2: CPU

Colocation members and user-requested devices:
  history/indices (VariableV2) /device:GPU:0
  history/indices/Assign (Assign) /device:GPU:0
  history/indices/read (Identity) /device:GPU:0
  history/save/Assign_1 (Assign) /device:GPU:0
  history_1/cond/strided_slice_1/Switch (Switch) /device:GPU:0
  history_1/cond/history_1/cond/strided_slice_5/_assign/Switch (RefSwitch) /device:GPU:0
  history_1/cond/history_1/cond/strided_slice_5/_assign (StridedSliceAssign) /device:GPU:0
  history_1/cond/history_1/cond/strided_slice_8/_assign (StridedSliceAssign) /device:GPU:0
  history_3/Assign_1 (Assign) /device:GPU:0

Registered kernels:
  device='CPU'
  device='GPU'; dtype in [DT_INT64]
  device='GPU'; dtype in [DT_DOUBLE]
  device='GPU'; dtype in [DT_FLOAT]
  device='GPU'; dtype in [DT_HALF]

	 [[Node: history/indices = VariableV2[container="", dtype=DT_INT32, shape=[10000], shared_name="", _device="/device:GPU:0"]()]]