code: def test_metricobservation_proto():
      obs = metrics_tracking.MetricObservation(-10, 5)
      proto = obs.to_proto()
      assert proto.value == [-10]
      assert proto.step == 5
      new_obs = metrics_tracking.MetricObservation.from_proto(proto)
      assert new_obs == obs
  
imports: import random
  import numpy
  import pytest
  from keras_tuner.backend.keras import losses
  from keras_tuner.backend.keras import metrics
  from keras_tuner.engine import metrics_tracking
label_desc: Use image node_id 13 for calling a global function with example usage: test_metricobservation_proto() without return types