from tensorflow.python.ops import math_ops

      # "accuracy/threshold_0.500000_mean" metric for binary classification.
      metrics = {("accuracy", "classes"): metrics_lib.streaming_accuracy}

    predictions = math_ops.sigmoid(logits)
    targets_float = math_ops.to_float(targets)

    default_metrics = self._default_eval_metrics()
    for metric_name, metric_op in default_metrics.items():
