code: def example_reading_spec(self):
      
      video_fields, video_decoders = (
          video_utils.VideoProblem.example_reading_spec(self))
      env_fields, env_decoders = env_problem.EnvProblem.example_reading_spec(self)
  
      # Remove raw observations field since we want to capture them as videos.
      env_fields.pop(env_problem.OBSERVATION_FIELD)
      env_decoders.pop(env_problem.OBSERVATION_FIELD)
  
      # Add frame number spec and decoder.
      env_fields[_FRAME_NUMBER_FIELD] = tf.FixedLenFeature((1,), tf.int64)
      env_decoders[
          _FRAME_NUMBER_FIELD] = tf.contrib.slim.tfexample_decoder.Tensor(
              _FRAME_NUMBER_FIELD)
  
      # Add video fields and decoders
      env_fields.update(video_fields)
      env_decoders.update(video_decoders)
      return env_fields, env_decoders
docs: Return a mix of env and video data fields and decoders.