code: def test_data(self):
      dtype_instance = [("attr_number", np.float64)]
  
      expected = np.array(
          [(n,) for n in range(30000)], dtype=dtype_instance
      )
  
      assert_array_equal(self.data["attr_relational"][0], expected)
  
imports: import datetime
  import os
  import sys
  from os.path import join
  from io import StringIO
  import numpy
  from numpy.testing import assert_array_almost_equal, assert_array_equal, assert_equal, assert_
  from pytest import raises
  from scipy.io.arff import loadarff
  from scipy.io.arff._arffread import read_header, ParseArffError
label_desc: Use image node_id 3 for calling the TestRelationalAttributeLong obj's underlying member method code with example usage: obj.test_data() without return types