code: def evalerror_01(self, preds, dtrain):
      labels = dtrain.get_label()
      return "error", float(sum(labels != (preds > 0.0))) / len(labels)
  
imports: import numpy
  import pytest
  import xgboost
  from xgboost import testing
  from xgboost.testing.metrics import check_precision_score, check_quantile_error
label_desc: Use image node_id 1 for calling the TestEvalMetrics obj's underlying member method code with example usage: obj.evalerror_01(preds, dtrain) and returns: str,  unknown