class_docstr: Record of the values of multiple executions of all metrics.
  
  It contains `MetricHistory` instances for the metrics.
  
  Args:
      metrics: List of strings of the names of the metrics.
class_docstr_tok: ["Record","of","the","values","of","multiple","executions","of","all","metrics",".","It","contains","`","MetricHistory","`","instances","for","the","metrics",".","Args",":","metrics",":","List","of","strings","of","the","names","of","the","metrics","."]
code: def register(self, name, direction=None):
      if self.exists(name):
          raise ValueError(f"Metric already exists: {name}")
      if direction is None:
          direction = infer_metric_direction(name)
      if direction is None:
          # Objective direction is handled separately, but
          # non-objective direction defaults to min.
          direction = "min"
      self.metrics[name] = MetricHistory(direction)
  
imports: import inspect
  import numpy
  import six
  from keras_tuner import protos
  from keras_tuner.api_export import keras_tuner_export
  from keras_tuner.backend import keras
label_desc: Use image node_id 4 for calling the MetricsTracker obj's underlying member method code with example usage: obj.register(name, direction) without return types