code: def test_from_summaries_null(model):
      model.from_summaries()
  
      assert model.distributions[0].scales[0] != 2.1
      assert model.distributions[1].scales[0] != 1.5
  
      assert_array_almost_equal(model._w_sum, [0.0, 0.0])
  
imports: import os
  import numpy
  import torch
  import pytest
  from pomegranate.bayes_classifier import BayesClassifier
  from pomegranate.distributions import Exponential
  from .distributions._utils import _test_initialization_raises_one_parameter
  from .distributions._utils import _test_initialization
  from .distributions._utils import _test_predictions
  from .distributions._utils import _test_efd_from_summaries
  from .distributions._utils import _test_raises
  from nose.tools import assert_raises
  from numpy.testing import assert_array_almost_equal
label_desc: Use image node_id 28 for calling a global function with example usage: test_from_summaries_null(model) without return types