code: def knn_test_data():
      n = 100
      data = np.random.normal(size=n * n).reshape((n, n))
      for _ in range(int(n * 0.3 * n)):
          data[np.random.randint(n), np.random.randint(n)] = np.nan
      return data
  
file_path: impyute/test/conftest.py
imports: import os
  import shutil
  import pytest
  import numpy
label_desc: Use image node_id 3 for calling a global function with example usage: knn_test_data() and returns: data