message: Fix lint errors in freeze_graph.py
diff: # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  # See the License for the specific language governing permissions and
  # limitations under the License.
  +"""Freeze a model to a GraphDef proto."""
  from absl import app, flags
  @@ -21,7 +22,8 @@ flags.DEFINE_string('model_path', None, 'Path to model to freeze')
  FLAGS = flags.FLAGS
  -def main(argv):
  +def main(unused_argv):
  + """Freeze a model to a GraphDef proto."""
  if FLAGS.use_tpu:
  dual_net.freeze_graph_tpu(FLAGS.model_path)
  else:
  