new_contents: # coding: pyxl
  
  from pyxl import html
  
  def test_no_filter():
      children = <div><p>One</p><p>Two</p></div>.children()
      assert len(children) == 2
      assert str(children[0]) == '<p>One</p>'
      assert str(children[1]) == '<p>Two</p>'
  
  def test_class_filter():
      div = <div><p class="yo">Hi</p><p>No</p><p class="yo">ho</p></div>
      children = div.children(selector='.yo')
      assert len(children) == 2
      assert str(children[0]) == '<p class="yo">Hi</p>'
      assert str(children[1]) == '<p class="yo">ho</p>'
  
  def test_id_filter():
      div = <div><p id="yo">Hi</p><p>No</p><p id="ho">ho</p></div>
      children = div.children(selector='#yo')
      assert len(children) == 1
      assert str(children[0]) == '<p id="yo">Hi</p>'
  
  def test_tag_filter():
      div = <div><div><p>Yo</p></div><p>Hi</p></div>
      children = div.children('p')
      assert len(children) == 1
      assert str(children[0]) == '<p>Hi</p>'
  
  def test_filter_negation():
      div = <div><p class="yo">Hi</p><p>No</p><p class="ho">ho</p></div>
      children = div.children(selector='.yo', exclude=True)
      assert len(children) == 2
      assert str(children[0]) == '<p>No</p>'
      assert str(children[1]) == '<p class="ho">ho</p>'
  
subject: Add tests for children method.