code: def _make_arr(na=0):
      arr = np.random.rand(10)
      arr[0:na] = np.nan
      return arr
  
file_path: sklearn-evaluation/tests/test_DataSelector.py
imports: from pathlib import Path
  import pytest
  import numpy
  import pandas
  from sklearn_evaluation.training import DataSelector
  from sklearn_evaluation.training.selector import expand_arguments, _with_prefix
  from sklearn_evaluation.exceptions import DataSelectorError
label_desc: Use image node_id 1 for calling a global function with example usage: _make_arr(na) and returns: arr