For example:

```python
c = tf.constant([[1,2,3,4], [-1,-2,-3,-4], [5,6,7,8]])

# Select two rows, one segment.
tf.sparse_segment_sum(c, tf.constant([0, 1]), tf.constant([0, 0]))
# => [[0 0 0 0]]

# Select two rows, two segment.
tf.sparse_segment_sum(c, tf.constant([0, 1]), tf.constant([0, 1]))
# => [[ 1  2  3  4]
#     [-1 -2 -3 -4]]

        `tf.train.confusion_matrix`.
    *   Add `tf.dtypes.` endpoint for every constant in dtypes.py. Moving
        endpoints in versions.py to corresponding endpoints in `tf.sysconfig.`
        and `tf.version.`. Moving all constants under `tf.saved_model`
        submodules to `tf.saved_model` module. New endpoints are added in V1 and

2107          ; mapped                 ; 025B          # 1.1  EULER CONSTANT
2108          ; valid                  ;      ; NV8    # 1.1  SCRUPLE
2109          ; mapped                 ; 00B0 0066     # 1.1  DEGREE FAHRENHEIT
210A          ; mapped                 ; 0067          # 1.1  SCRIPT SMALL G
210B..210E    ; mapped                 ; 0068          # 1.1  SCRIPT CAPITAL H..PLANCK CONSTANT

            tuple_value {
            }
          }
        }
      }
      dependencies {
        node_id: 5
        local_name: "capture_0"
      }
    }
    nodes {
      constant {
        operation: "Const"
      }
      registered_name: "tf.TrackableConstant"
    }
    concrete_functions {
      key: "__inference_<lambda>_18"
      value {
        bound_inputs: 5