node {
  name  : "x_const"
  op    : "Const"
  attr {
    key: "value"
    value {
      tensor {
        dtype: DT_INT32
        tensor_shape { dim { size: 1 } }
        int_val: 1
      }
    }
  }
  attr { key  : "dtype" value { type: DT_INT32 } }
}
node {
  name  : "y_const"
  op    : "Const"
  attr {
    key: "value"
    value {
      tensor {
        dtype: DT_INT32
        tensor_shape { dim { size: 1 } }
        int_val: 2
      }
    }
  }
  attr { key: "dtype" value { type: DT_INT32 } }
}
node {
  name  : "x_y_sum"
  op    : "Add"
  input : "x_const"
  input : "y_const"
  attr { key  : "T" value { type: DT_INT32 } }
}
node {
  name  : "z"
  op    : "SomeUnknownOp"
  input : "x_const"
}
node {
  name  : "z_identity"
  op    : "Identity"
  input : "z:1"
  attr { key  : "T" value { type: DT_INT32 } }
}
node {
  name  : "x_z_sum"
  op    : "Add"
  input : "x_const"
  input : "z_identity"
  attr { key  : "T" value { type: DT_INT32 } }
}
versions {
  producer: 15
}