text: """Testing module io."""
  
  import json
  
  import numpy as np
  
  from treem.io import TreemEncoder
  
  
  def test_io_encoder():
      """Tests JSON encoder."""
      data = [[1, 2, 3], np.array(range(4, 7)), {7, 8, 9}, 0, "a"]
      assert json.dumps(data, cls=TreemEncoder) ==\
          '[[1, 2, 3], [4, 5, 6], [8, 9, 7], 0, "a"]'
  